Refactor truststore merger logic

- Merge PemTruststore and JavaTruststore into Truststore
- Rename controller classes to be consistent
- Remove duplicated methods

Issue-ID: DCAEGEN2-2253
Signed-off-by: Piotr Marcinkiewicz <piotr.marcinkiewicz@nokia.com>
Change-Id: I3270cd9811e5eaf360ceea0d0ca99be1155eaf00

43 files changed, 714 insertions, 943 deletions

diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/TrustStoreMerger.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/TrustStoreMerger.java
index babd32e2..7f53331f 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/TrustStoreMerger.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/TrustStoreMerger.java
@@ -22,12 +22,9 @@ package org.onap.oom.truststoremerger;
 import java.util.List;
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.TruststoreFileFactory;
-import org.onap.oom.truststoremerger.certification.file.TruststoreFilesListProvider;
-import org.onap.oom.truststoremerger.certification.file.model.Truststore;
-import org.onap.oom.truststoremerger.certification.file.provider.FileManager;
-import org.onap.oom.truststoremerger.certification.file.provider.PasswordReader;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
+import org.onap.oom.truststoremerger.merger.TruststoreFilesProvider;
+import org.onap.oom.truststoremerger.merger.model.Truststore;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
 import org.onap.oom.truststoremerger.configuration.MergerConfigurationProvider;
 import org.onap.oom.truststoremerger.configuration.model.MergerConfiguration;
 import org.onap.oom.truststoremerger.configuration.path.DelimitedPathsReader;
@@ -69,8 +66,9 @@ class TrustStoreMerger {
         baseFile.createBackup();
 
         for (int i = SECOND_TRUSTSTORE_INDEX; i < truststoreFilesList.size(); i++) {
-            List<CertificateWithAlias> certificateWrappers = truststoreFilesList.get(i).getCertificates();
-            baseFile.addCertificate(certificateWrappers);
+            Truststore truststore = truststoreFilesList.get(i);
+            List<CertificateWithAlias> certificateWrappers = truststore.getCertificates();
+            baseFile.addCertificates(certificateWrappers);
         }
 
         baseFile.saveFile();
@@ -87,13 +85,9 @@ class TrustStoreMerger {
         return factory.createConfiguration();
     }
 
-    private List<Truststore> getTruststoreFiles(MergerConfiguration configuration) throws ExitableException {
-        TruststoreFileFactory truststoreFileFactory = new TruststoreFileFactory(new FileManager(),
-            new PasswordReader());
-        TruststoreFilesListProvider truststoreFilesListProvider = new TruststoreFilesListProvider(
-            truststoreFileFactory);
-        return truststoreFilesListProvider
-            .getTruststoreFilesList(
+    private static List<Truststore> getTruststoreFiles(MergerConfiguration configuration) throws ExitableException {
+        return TruststoreFilesProvider
+            .getTruststoreFiles(
                 configuration.getTruststoreFilePaths(),
                 configuration.getTruststoreFilePasswordPaths()
             );
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/api/CertificateConstants.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/api/CertificateConstants.java
index 68c5d13c..75756aa1 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/api/CertificateConstants.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/api/CertificateConstants.java
@@ -21,8 +21,8 @@ package org.onap.oom.truststoremerger.api;
 
 public class CertificateConstants {
 
-    public static final String JKS_INSTANCE = "JKS";
-    public static final String PKCS12_INSTANCE = "PKCS12";
+    public static final String JKS_TYPE = "JKS";
+    public static final String PKCS12_TYPE = "PKCS12";
     public static final String X_509_CERTIFICATE = "X.509";
     public static final String BOUNCY_CASTLE_PROVIDER = "BC";
 
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/TruststoreFileFactory.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/TruststoreFileFactory.java
deleted file mode 100644
index d93409b6..00000000
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/TruststoreFileFactory.java
+++ /dev/null
@@ -1,99 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file;
-
-import org.onap.oom.truststoremerger.certification.file.model.JavaTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.PemTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.Truststore;
-
-import java.io.File;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreFileFactoryException;
-import org.onap.oom.truststoremerger.certification.file.provider.CertificateStoreControllerFactory;
-import org.onap.oom.truststoremerger.certification.file.provider.FileManager;
-import org.onap.oom.truststoremerger.certification.file.provider.JavaCertificateStoreController;
-import org.onap.oom.truststoremerger.certification.file.provider.PasswordReader;
-import org.onap.oom.truststoremerger.certification.file.provider.PemCertificateController;
-
-public class TruststoreFileFactory {
-
-    private static final String JKS_EXTENSION = ".jks";
-    private static final String P12_EXTENSION = ".p12";
-    private static final String PEM_EXTENSION = ".pem";
-    private static final String FILE_DOES_NOT_EXIST_MSG_TEMPLATE = "File: %s does not exist";
-    private static final String UNKNOWN_TRUSTSTORE_TYPE_MSG_TEMPLATE = "Unknown truststore extension type: %s";
-
-    private final FileManager fileManager;
-    private final PasswordReader passwordReader;
-    private final CertificateStoreControllerFactory certificateStoreControllerFactory =
-        new CertificateStoreControllerFactory();
-
-    public TruststoreFileFactory(FileManager fileManager, PasswordReader passwordReader) {
-        this.fileManager = fileManager;
-        this.passwordReader = passwordReader;
-    }
-
-    public Truststore create(String truststoreFilePath, String truststorePasswordPath)
-        throws TruststoreFileFactoryException, PasswordReaderException, KeystoreInstanceException, LoadTruststoreException {
-        File truststoreFile = new File(truststoreFilePath);
-        if (!fileManager.checkIfFileExists(truststoreFile)) {
-            throw new TruststoreFileFactoryException(String.format(FILE_DOES_NOT_EXIST_MSG_TEMPLATE, truststoreFile));
-        }
-        return createTypedTruststore(truststoreFile, truststorePasswordPath);
-    }
-
-    private Truststore createTypedTruststore(File truststoreFile, String truststorePasswordPath)
-        throws KeystoreInstanceException, PasswordReaderException, LoadTruststoreException, TruststoreFileFactoryException {
-        String extension = fileManager.getExtension(truststoreFile);
-        switch (extension) {
-            case JKS_EXTENSION:
-                return createJksTruststore(truststoreFile, truststorePasswordPath);
-            case P12_EXTENSION:
-                return createP12Truststore(truststoreFile, truststorePasswordPath);
-            case PEM_EXTENSION:
-                return createPemTruststore(truststoreFile);
-            default:
-                throw new TruststoreFileFactoryException(
-                    String.format(UNKNOWN_TRUSTSTORE_TYPE_MSG_TEMPLATE, extension));
-        }
-    }
-
-    private JavaTruststore createJksTruststore(File truststoreFile, String truststorePasswordPath)
-        throws PasswordReaderException, LoadTruststoreException, KeystoreInstanceException {
-        String password = passwordReader.readPassword(new File(truststorePasswordPath));
-        JavaCertificateStoreController storeController = certificateStoreControllerFactory
-            .createLoadedJksCertificateStoreController(truststoreFile, password);
-        return new JavaTruststore(truststoreFile, storeController);
-    }
-
-    private JavaTruststore createP12Truststore(File truststoreFile, String truststorePasswordPath)
-        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
-        String password = passwordReader.readPassword(new File(truststorePasswordPath));
-        JavaCertificateStoreController storeController = certificateStoreControllerFactory
-            .createLoadedPkcs12CertificateStoreController(truststoreFile, password);
-        return new JavaTruststore(truststoreFile, storeController);
-    }
-
-    private PemTruststore createPemTruststore(File truststoreFile) {
-        return new PemTruststore(truststoreFile, new PemCertificateController(truststoreFile));
-    }
-}
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststore.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststore.java
deleted file mode 100644
index d46fba1e..00000000
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststore.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file.model;
-
-import java.io.File;
-import java.util.List;
-import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.exception.WriteTruststoreFileException;
-import org.onap.oom.truststoremerger.certification.file.provider.JavaCertificateStoreController;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class JavaTruststore extends Truststore {
-
-    private static final Logger LOGGER = LoggerFactory.getLogger(JavaTruststore.class);
-    private final JavaCertificateStoreController storeController;
-
-    public JavaTruststore(File truststoreFile, JavaCertificateStoreController storeController) {
-        super(truststoreFile);
-        this.storeController = storeController;
-    }
-
-    @Override
-    public List<CertificateWithAlias> getCertificates() throws ExitableException {
-        LOGGER.debug("Attempt ro read certificates from file: {} ", this.getFile().getPath());
-        return storeController.getNotEmptyCertificateList();
-    }
-
-    @Override
-    public void addCertificate(List<CertificateWithAlias> certificates) throws ExitableException {
-        LOGGER.debug("Attempt to add certificates for saving to file");
-        storeController.addCertificates(certificates);
-    }
-
-    @Override
-    public void saveFile() throws WriteTruststoreFileException {
-        LOGGER.debug("Attempt to save file: {}", this.getFile().getPath());
-        storeController.saveFile();
-    }
-}
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststore.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststore.java
deleted file mode 100644
index 36195267..00000000
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststore.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file.model;
-
-import java.io.File;
-import java.util.List;
-import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.provider.PemCertificateController;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class PemTruststore extends Truststore {
-
-    private static final Logger LOGGER = LoggerFactory.getLogger(PemTruststore.class);
-    private final PemCertificateController pemCertificateController;
-
-    public PemTruststore(File truststoreFile, PemCertificateController pemCertificateController) {
-        super(truststoreFile);
-        this.pemCertificateController = pemCertificateController;
-    }
-
-    @Override
-    public List<CertificateWithAlias> getCertificates() throws ExitableException {
-        LOGGER.debug("Attempt ro read certificates from file: {}", this.getFile().getPath());
-        return pemCertificateController.getNotEmptyCertificateList();
-    }
-
-    @Override
-    public void addCertificate(List<CertificateWithAlias> certificates) throws ExitableException {
-        LOGGER.debug("Attempt to add certificates for saving to file");
-        pemCertificateController.addCertificates(certificates);
-    }
-
-    @Override
-    public void saveFile() throws ExitableException {
-        LOGGER.debug("Attempt to save file: {}", this.getFile().getPath());
-        pemCertificateController.saveFile();
-    }
-
-}
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/CertificateStoreControllerFactory.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/CertificateStoreControllerFactory.java
deleted file mode 100644
index 66e2aed2..00000000
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/CertificateStoreControllerFactory.java
+++ /dev/null
@@ -1,61 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file.provider;
-
-import static org.onap.oom.truststoremerger.api.CertificateConstants.JKS_INSTANCE;
-import static org.onap.oom.truststoremerger.api.CertificateConstants.PKCS12_INSTANCE;
-
-import java.io.File;
-import java.security.KeyStore;
-import java.security.KeyStoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class CertificateStoreControllerFactory {
-
-    private static final Logger LOGGER = LoggerFactory.getLogger(CertificateStoreControllerFactory.class);
-
-    public JavaCertificateStoreController createLoadedJksCertificateStoreController(File certFile, String certPassword)
-        throws LoadTruststoreException, KeystoreInstanceException {
-        return createLoadedCertificateStoreController(certFile, certPassword, JKS_INSTANCE);
-    }
-
-    public JavaCertificateStoreController createLoadedPkcs12CertificateStoreController(File certFile, String certPassword)
-        throws KeystoreInstanceException, LoadTruststoreException {
-        return createLoadedCertificateStoreController(certFile, certPassword, PKCS12_INSTANCE);
-    }
-
-    private JavaCertificateStoreController createLoadedCertificateStoreController(File certFile, String certPassword,
-        String instanceType)
-        throws LoadTruststoreException, KeystoreInstanceException {
-        try {
-            JavaCertificateStoreController javaCertificateStoreController = new JavaCertificateStoreController(
-                KeyStore.getInstance(instanceType), certFile, certPassword);
-            javaCertificateStoreController.loadFile();
-            return javaCertificateStoreController;
-        } catch (KeyStoreException e) {
-            LOGGER.error("Cannot initialize Java Keystore instance");
-            throw new KeystoreInstanceException(e);
-        }
-    }
-}
-
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/Truststore.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/BackupCreator.java
index 153805a7..9187393e 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/model/Truststore.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/BackupCreator.java
@@ -17,46 +17,32 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.model;
+package org.onap.oom.truststoremerger.common;
 
 import java.io.File;
 import java.io.FileOutputStream;
 import java.nio.file.Files;
-import java.util.List;
-import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.exception.CreateBackupException;
+import org.onap.oom.truststoremerger.merger.exception.CreateBackupException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public abstract class Truststore {
+public final class BackupCreator {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(Truststore.class);
+    private static final Logger LOGGER = LoggerFactory.getLogger(BackupCreator.class);
     private static final String BACKUP_EXTENSION = ".bak";
-    private final File file;
 
-    Truststore(File file) {
-        this.file = file;
+    private BackupCreator() {
     }
 
-    public abstract List<CertificateWithAlias> getCertificates() throws ExitableException;
-
-    public abstract void addCertificate(List<CertificateWithAlias> certificates) throws ExitableException;
-
-    public abstract void saveFile() throws ExitableException;
-
-    public File getFile() {
-        return file;
-    }
-
-    public void createBackup() throws CreateBackupException {
+    public static void createBackup(File file) throws CreateBackupException {
         LOGGER.debug("Create backup of file: {}", file.getPath());
         String backupFilePath = file.getAbsolutePath() + BACKUP_EXTENSION;
         try (FileOutputStream fileOutputStream = new FileOutputStream(backupFilePath)) {
             Files.copy(file.toPath(), fileOutputStream);
         } catch (Exception e) {
-            LOGGER.error("Cannot create backup of file: {} ", getFile().getPath());
+            LOGGER.error("Cannot create backup of file: {} ", file.getPath());
             throw new CreateBackupException(e);
         }
+        LOGGER.debug("Backup was successfully created in: {}", backupFilePath);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/FileManager.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/ExtensionResolver.java
index 12029ade..af792c48 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/FileManager.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/ExtensionResolver.java
@@ -17,15 +17,17 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.common;
 
 import java.io.File;
 
-public class FileManager {
+public final class ExtensionResolver {
 
     private static final int INDEX_NOT_FOUND = -1;
 
-    public String getExtension(File file) {
+    private ExtensionResolver() {}
+
+    public static String get(File file) {
         int extStartIndex = file.getName().lastIndexOf(".");
         if (extStartIndex == INDEX_NOT_FOUND) {
             return "";
@@ -33,7 +35,7 @@ public class FileManager {
         return file.getName().substring(extStartIndex).toLowerCase();
     }
 
-    public boolean checkIfFileExists(File file) {
+    public static boolean checkIfFileExists(File file) {
         return file.exists();
     }
 
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/PasswordReader.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/PasswordReader.java
index d7da53b0..d84be5ac 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/PasswordReader.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/common/PasswordReader.java
@@ -17,17 +17,21 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.common;
 
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+
+public final class PasswordReader {
 
-public class PasswordReader {
     private static final String COULD_NOT_READ_PASSWORD_FROM_FILE_MSG_TEMPLATE = "Could not read password from file: %s";
 
-    public String readPassword(File file) throws PasswordReaderException {
+    private PasswordReader() {
+    }
+
+    public static String readPassword(File file) throws PasswordReaderException {
         try {
             return Files.readString(file.toPath());
         } catch (IOException e) {
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/MergerConfigurationException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/MergerConfigurationException.java
index 90a75d91..4bdfd9f4 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/MergerConfigurationException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/MergerConfigurationException.java
@@ -24,7 +24,7 @@ import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class MergerConfigurationException extends ExitableException {
 
-    public MergerConfigurationException(String message) {
-        super(message, ExitStatus.MERGER_CONFIGURATION_EXCEPTION);
+    public MergerConfigurationException(String errorMessage) {
+        super(errorMessage, ExitStatus.MERGER_CONFIGURATION_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/TruststoresPathsProviderException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/TruststoresPathsProviderException.java
index dda53e32..6089d314 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/TruststoresPathsProviderException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/configuration/exception/TruststoresPathsProviderException.java
@@ -24,7 +24,7 @@ import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class TruststoresPathsProviderException extends ExitableException {
 
-    public TruststoresPathsProviderException(String message) {
-        super(message, ExitStatus.TRUSTSTORES_PATHS_PROVIDER_EXCEPTION);
+    public TruststoresPathsProviderException(String errorMessage) {
+        super(errorMessage, ExitStatus.TRUSTSTORES_PATHS_PROVIDER_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/TruststoreFilesListProvider.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/TruststoreFilesProvider.java
index 92e3c2a8..9108fb69 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/TruststoreFilesListProvider.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/TruststoreFilesProvider.java
@@ -17,37 +17,35 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file;
-
-import org.onap.oom.truststoremerger.certification.file.model.Truststore;
+package org.onap.oom.truststoremerger.merger;
 
 import java.util.ArrayList;
 import java.util.List;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreFileFactoryException;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreFileFactoryException;
+import org.onap.oom.truststoremerger.merger.model.TruststoreFactory;
+import org.onap.oom.truststoremerger.merger.model.Truststore;
 
-public class TruststoreFilesListProvider {
+public class TruststoreFilesProvider {
 
-    private final TruststoreFileFactory truststoreFileFactory;
 
-    public TruststoreFilesListProvider(TruststoreFileFactory truststoreFileFactory) {
-        this.truststoreFileFactory = truststoreFileFactory;
+    private TruststoreFilesProvider() {
     }
 
-    public List<Truststore> getTruststoreFilesList(List<String> truststoreFilePaths,
+    public static List<Truststore> getTruststoreFiles(List<String> truststoreFilePaths,
         List<String> truststoreFilePasswordPaths)
         throws LoadTruststoreException, PasswordReaderException, TruststoreFileFactoryException, KeystoreInstanceException {
-        List<Truststore> truststoreFilesList = new ArrayList<>();
+        List<Truststore> truststoreFiles = new ArrayList<>();
         for (int i = 0; i < truststoreFilePaths.size(); i++) {
             String truststorePath = truststoreFilePaths.get(i);
             String passwordPath = truststoreFilePasswordPaths.get(i);
 
-            Truststore truststore = truststoreFileFactory.create(truststorePath, passwordPath);
-            truststoreFilesList.add(truststore);
+            Truststore truststore = TruststoreFactory.create(truststorePath, passwordPath);
+            truststoreFiles.add(truststore);
         }
 
-        return truststoreFilesList;
+        return truststoreFiles;
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/AliasConflictException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/AliasConflictException.java
index a4102d9f..71df3a45 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/AliasConflictException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/AliasConflictException.java
@@ -17,15 +17,15 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class AliasConflictException extends ExitableException {
 
-    public AliasConflictException(String message) {
-        super(message, ExitStatus.ALIAS_CONFLICT_EXCEPTION);
+    public AliasConflictException(String errorMessage) {
+        super(errorMessage, ExitStatus.ALIAS_CONFLICT_EXCEPTION);
     }
 
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/CreateBackupException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/CreateBackupException.java
index a21f7013..f655a9f5 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/CreateBackupException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/CreateBackupException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class CreateBackupException extends ExitableException {
 
-    public CreateBackupException(Exception e) {
-        super(e, ExitStatus.CREATE_BACKUP_EXCEPTION);
+    public CreateBackupException(Exception cause) {
+        super(cause, ExitStatus.CREATE_BACKUP_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/KeystoreInstanceException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/KeystoreInstanceException.java
index c5bcc3ca..99a955d9 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/KeystoreInstanceException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/KeystoreInstanceException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class KeystoreInstanceException extends ExitableException {
 
-    public KeystoreInstanceException(Throwable e) {
-        super(e, ExitStatus.KEYSTORE_INSTANCE_EXCEPTION);
+    public KeystoreInstanceException(Exception cause) {
+        super(cause, ExitStatus.KEYSTORE_INSTANCE_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/LoadTruststoreException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/LoadTruststoreException.java
index b8bb53fa..810bf556 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/LoadTruststoreException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/LoadTruststoreException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class LoadTruststoreException extends ExitableException {
 
-    public LoadTruststoreException(Throwable e) {
-        super(e, ExitStatus.TRUSTSTORE_LOAD_FILE_EXCEPTION);
+    public LoadTruststoreException(Exception cause) {
+        super(cause, ExitStatus.TRUSTSTORE_LOAD_FILE_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/MissingTruststoreException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/MissingTruststoreException.java
index c502d6b6..9065c9d3 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/MissingTruststoreException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/MissingTruststoreException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class MissingTruststoreException extends ExitableException {
 
-    public MissingTruststoreException(String message) {
-        super(message, ExitStatus.MISSING_TRUSTSTORE_EXCEPTION);
+    public MissingTruststoreException(String errorMessage) {
+        super(errorMessage, ExitStatus.MISSING_TRUSTSTORE_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/PasswordReaderException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/PasswordReaderException.java
index d601d229..9f9d2e27 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/PasswordReaderException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/PasswordReaderException.java
@@ -17,13 +17,13 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class PasswordReaderException extends ExitableException {
-    public PasswordReaderException(String message) {
-        super(message, ExitStatus.PASSWORD_READER_EXCEPTION);
+    public PasswordReaderException(String errorMessage) {
+        super(errorMessage, ExitStatus.PASSWORD_READER_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/TruststoreDataOperationException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/TruststoreDataOperationException.java
index cf848f79..c18cb006 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/TruststoreDataOperationException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/TruststoreDataOperationException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class TruststoreDataOperationException extends ExitableException {
 
-    public TruststoreDataOperationException(Exception e) {
-        super(e, ExitStatus.TRUSTSTORE_DATA_OPERATION_EXCEPTION);
+    public TruststoreDataOperationException(Exception cause) {
+        super(cause, ExitStatus.TRUSTSTORE_DATA_OPERATION_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/TruststoreFileFactoryException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/TruststoreFileFactoryException.java
index 18349fd4..f802a9d3 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/TruststoreFileFactoryException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/TruststoreFileFactoryException.java
@@ -17,14 +17,14 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class TruststoreFileFactoryException extends ExitableException {
-    public TruststoreFileFactoryException(String message) {
-        super(message, ExitStatus.TRUSTSTORE_FILE_FACTORY_EXCEPTION);
+    public TruststoreFileFactoryException(String errorMessage) {
+        super(errorMessage, ExitStatus.TRUSTSTORE_FILE_FACTORY_EXCEPTION);
     }
 
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/WriteTruststoreFileException.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/WriteTruststoreFileException.java
index a5e02b3c..fe368868 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/exception/WriteTruststoreFileException.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/exception/WriteTruststoreFileException.java
@@ -18,14 +18,14 @@
  */
 
 
-package org.onap.oom.truststoremerger.certification.file.exception;
+package org.onap.oom.truststoremerger.merger.exception;
 
 import org.onap.oom.truststoremerger.api.ExitStatus;
 import org.onap.oom.truststoremerger.api.ExitableException;
 
 public class WriteTruststoreFileException extends ExitableException {
 
-    public WriteTruststoreFileException(Exception e) {
-        super(e, ExitStatus.WRITE_TRUSTSTORE_FILE_EXCEPTION);
+    public WriteTruststoreFileException(Exception cause) {
+        super(cause, ExitStatus.WRITE_TRUSTSTORE_FILE_EXCEPTION);
     }
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/JavaCertificateStoreController.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/JavaTruststore.java
index a4b129c9..e3a03996 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/JavaCertificateStoreController.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/JavaTruststore.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -28,33 +28,40 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.exception.AliasConflictException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.MissingTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreDataOperationException;
-import org.onap.oom.truststoremerger.certification.file.exception.WriteTruststoreFileException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAliasFactory;
+import org.onap.oom.truststoremerger.merger.exception.AliasConflictException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.MissingTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreDataOperationException;
+import org.onap.oom.truststoremerger.merger.exception.WriteTruststoreFileException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAliasFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class JavaCertificateStoreController implements CertificateController {
+public final class JavaTruststore extends Truststore {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(JavaCertificateStoreController.class);
+    private static final Logger LOGGER = LoggerFactory.getLogger(JavaTruststore.class);
 
     private final CertificateWithAliasFactory factory = new CertificateWithAliasFactory();
     private final KeyStore keyStore;
-    private final File storeFile;
     private final String password;
 
 
-    public JavaCertificateStoreController(KeyStore keyStore, File storeFile, String password) {
+    private JavaTruststore(KeyStore keyStore, File storeFile, String password) {
+        super(storeFile);
         this.keyStore = keyStore;
-        this.storeFile = storeFile;
         this.password = password;
     }
 
-    public List<CertificateWithAlias> getNotEmptyCertificateList() throws ExitableException {
+    public static JavaTruststore createWithLoadingFile(KeyStore keyStore, File storeFile, String password)
+        throws LoadTruststoreException {
+        JavaTruststore javaTruststore = new JavaTruststore(keyStore, storeFile, password);
+        javaTruststore.loadFile();
+        return javaTruststore;
+    }
+
+    public List<CertificateWithAlias> getCertificates() throws ExitableException {
+        LOGGER.debug("Attempt to read certificates from file: {}", storeFile.getPath());
         List<String> aliases = getTruststoreAliases();
         if (aliases.isEmpty()) {
             throw new MissingTruststoreException("Missing certificate aliases in file: " + storeFile.getPath());
@@ -64,6 +71,7 @@ public class JavaCertificateStoreController implements CertificateController {
 
     public void addCertificates(List<CertificateWithAlias> certificatesWithAliases)
         throws ExitableException {
+        LOGGER.debug("Attempt to add certificates for saving to file");
         if (getTruststoreAliases().isEmpty()) {
             throw new MissingTruststoreException("Missing certificate aliases in file: " + storeFile.getPath());
         }
@@ -73,7 +81,8 @@ public class JavaCertificateStoreController implements CertificateController {
     }
 
     public void saveFile() throws WriteTruststoreFileException {
-        try (FileOutputStream outputStream = new FileOutputStream(this.storeFile)) {
+        LOGGER.debug("Attempt to save file: {}", storeFile.getPath());
+        try (FileOutputStream outputStream = new FileOutputStream(storeFile)) {
             keyStore.store(outputStream, this.password.toCharArray());
         } catch (Exception e) {
             LOGGER.error("Cannot write truststore file");
@@ -81,11 +90,11 @@ public class JavaCertificateStoreController implements CertificateController {
         }
     }
 
-    public void loadFile() throws LoadTruststoreException {
+    private void loadFile() throws LoadTruststoreException {
         try {
-            keyStore.load(new FileInputStream(this.storeFile), this.password.toCharArray());
+            keyStore.load(new FileInputStream(storeFile), this.password.toCharArray());
         } catch (Exception e) {
-            LOGGER.error("Cannot load file: {}", this.storeFile.getPath());
+            LOGGER.error("Cannot load file: {}", storeFile.getPath());
             throw new LoadTruststoreException(e);
         }
     }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/JavaTruststoreFactory.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/JavaTruststoreFactory.java
new file mode 100644
index 00000000..d40cfb1a
--- /dev/null
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/JavaTruststoreFactory.java
@@ -0,0 +1,51 @@
+/*============LICENSE_START=======================================================
+ * oom-truststore-merger
+ * ================================================================================
+ * Copyright (C) 2020 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.oom.truststoremerger.merger.model;
+
+import java.io.File;
+import java.security.KeyStore;
+import java.security.KeyStoreException;
+import org.onap.oom.truststoremerger.common.PasswordReader;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class JavaTruststoreFactory {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(JavaTruststoreFactory.class);
+
+    private JavaTruststoreFactory() {
+    }
+
+    public static Truststore create(File certFile, String truststorePasswordPath, String keystoreType)
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        String password = PasswordReader.readPassword(new File(truststorePasswordPath));
+        try {
+            return JavaTruststore
+                .createWithLoadingFile(KeyStore.getInstance(keystoreType), certFile, password);
+        } catch (KeyStoreException e) {
+            LOGGER.error("Cannot initialize Java Keystore instance");
+            throw new KeystoreInstanceException(e);
+        }
+    }
+}
+
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/PemCertificateController.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/PemTruststore.java
index 9ff42b87..d04a01b1 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/PemCertificateController.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/PemTruststore.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
 
 import static org.onap.oom.truststoremerger.api.CertificateConstants.BOUNCY_CASTLE_PROVIDER;
 import static org.onap.oom.truststoremerger.api.CertificateConstants.X_509_CERTIFICATE;
@@ -37,30 +37,30 @@ import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.bouncycastle.openssl.jcajce.JcaMiscPEMGenerator;
 import org.bouncycastle.util.io.pem.PemObjectGenerator;
 import org.bouncycastle.util.io.pem.PemWriter;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAliasFactory;
-import org.onap.oom.truststoremerger.certification.file.exception.MissingTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreDataOperationException;
-import org.onap.oom.truststoremerger.certification.file.exception.WriteTruststoreFileException;
+import org.onap.oom.truststoremerger.merger.exception.MissingTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreDataOperationException;
+import org.onap.oom.truststoremerger.merger.exception.WriteTruststoreFileException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAliasFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class PemCertificateController implements CertificateController {
+public class PemTruststore extends Truststore {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(PemCertificateController.class);
+    private static final Logger LOGGER = LoggerFactory.getLogger(PemTruststore.class);
 
     private static final boolean APPEND_TO_FILE = true;
 
     private final CertificateWithAliasFactory factory = new CertificateWithAliasFactory();
     private final List<CertificateWithAlias> certificatesToBeSaved = new ArrayList<>();
-    private final File file;
 
-    public PemCertificateController(File file) {
-        this.file = file;
+    public PemTruststore(File storeFile) {
+        super(storeFile);
     }
 
-    public List<CertificateWithAlias> getNotEmptyCertificateList()
+    public List<CertificateWithAlias> getCertificates()
         throws TruststoreDataOperationException, MissingTruststoreException {
+        LOGGER.debug("Attempt to read certificates from file: {}", storeFile.getPath());
         if (isFileWithoutPemCertificate()) {
             throw new MissingTruststoreException("File does not contain any certificate");
         }
@@ -70,14 +70,16 @@ public class PemCertificateController implements CertificateController {
 
     public void addCertificates(List<CertificateWithAlias> certificates)
         throws TruststoreDataOperationException, MissingTruststoreException {
+        LOGGER.debug("Attempt to add certificates for saving to file");
         if (isFileWithoutPemCertificate()) {
-            LOGGER.error("File does not contain any certificate. File path: {} ", this.file.getPath());
+            LOGGER.error("File does not contain any certificate. File path: {} ", storeFile.getPath());
             throw new MissingTruststoreException("File does not contain any certificate");
         }
         certificatesToBeSaved.addAll(certificates);
     }
 
     public void saveFile() throws WriteTruststoreFileException, TruststoreDataOperationException {
+        LOGGER.debug("Attempt to save file: {}", storeFile.getPath());
         List<Certificate> certificates = certificatesToBeSaved.stream()
             .map(CertificateWithAlias::getCertificate)
             .collect(Collectors.toList());
@@ -104,19 +106,17 @@ public class PemCertificateController implements CertificateController {
         return sw.toString();
     }
 
-
     private List<Certificate> extractCertificatesFromFile() throws TruststoreDataOperationException {
-        try (FileInputStream inputStream = new FileInputStream(this.file)) {
+        try (FileInputStream inputStream = new FileInputStream(storeFile)) {
             Security.addProvider(new BouncyCastleProvider());
             CertificateFactory factory = CertificateFactory.getInstance(X_509_CERTIFICATE, BOUNCY_CASTLE_PROVIDER);
             return new ArrayList<>(factory.generateCertificates(inputStream));
         } catch (Exception e) {
-            LOGGER.error("Cannot read certificates from file: {}", this.file.getPath());
+            LOGGER.error("Cannot read certificates from file: {}", storeFile.getPath());
             throw new TruststoreDataOperationException(e);
         }
     }
 
-
     private List<PemObjectGenerator> transformToPemGenerators(List<Certificate> certificates)
         throws TruststoreDataOperationException {
         List<PemObjectGenerator> generators = new ArrayList<>();
@@ -145,7 +145,7 @@ public class PemCertificateController implements CertificateController {
 
     private void appendToFile(String certificatesAsString) throws WriteTruststoreFileException {
         try {
-            FileOutputStream fileOutputStream = new FileOutputStream(this.file, APPEND_TO_FILE);
+            FileOutputStream fileOutputStream = new FileOutputStream(storeFile, APPEND_TO_FILE);
             fileOutputStream.write(certificatesAsString.getBytes());
         } catch (Exception e) {
             LOGGER.error("Cannot write certificates to file");
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/CertificateController.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/Truststore.java
index f2ed2c45..2c3acf49 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/CertificateController.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/Truststore.java
@@ -17,17 +17,30 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
 
+import java.io.File;
 import java.util.List;
 import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
+import org.onap.oom.truststoremerger.merger.exception.CreateBackupException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
+import org.onap.oom.truststoremerger.common.BackupCreator;
 
-public interface CertificateController {
+public abstract class Truststore {
 
-    List<CertificateWithAlias> getNotEmptyCertificateList() throws ExitableException;
+    final File storeFile;
 
-    void addCertificates(List<CertificateWithAlias> certificates) throws ExitableException;
+    public Truststore(File storeFile) {
+        this.storeFile = storeFile;
+    }
 
-    void saveFile() throws ExitableException;
+    public void createBackup() throws CreateBackupException {
+        BackupCreator.createBackup(storeFile);
+    }
+
+    public abstract List<CertificateWithAlias> getCertificates() throws ExitableException;
+
+    public abstract void addCertificates(List<CertificateWithAlias> certificates) throws ExitableException;
+
+    public abstract void saveFile() throws ExitableException;
 }
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/TruststoreFactory.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/TruststoreFactory.java
new file mode 100644
index 00000000..7e4b71e3
--- /dev/null
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/TruststoreFactory.java
@@ -0,0 +1,69 @@
+/*============LICENSE_START=======================================================
+ * oom-truststore-merger
+ * ================================================================================
+ * Copyright (C) 2020 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.oom.truststoremerger.merger.model;
+
+import static org.onap.oom.truststoremerger.api.CertificateConstants.JKS_TYPE;
+import static org.onap.oom.truststoremerger.api.CertificateConstants.PKCS12_TYPE;
+
+import java.io.File;
+import org.onap.oom.truststoremerger.common.ExtensionResolver;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreFileFactoryException;
+
+public class TruststoreFactory {
+
+    private static final String JKS_EXTENSION = ".jks";
+    private static final String P12_EXTENSION = ".p12";
+    private static final String PEM_EXTENSION = ".pem";
+    private static final String FILE_DOES_NOT_EXIST_MSG_TEMPLATE = "File: %s does not exist";
+    private static final String UNKNOWN_TRUSTSTORE_TYPE_MSG_TEMPLATE = "Unknown truststore extension type: %s";
+
+
+    private TruststoreFactory() {
+    }
+
+    public static Truststore create(String truststoreFilePath, String truststorePasswordPath)
+        throws TruststoreFileFactoryException, PasswordReaderException, KeystoreInstanceException, LoadTruststoreException {
+        File truststoreFile = new File(truststoreFilePath);
+        if (!ExtensionResolver.checkIfFileExists(truststoreFile)) {
+            throw new TruststoreFileFactoryException(String.format(FILE_DOES_NOT_EXIST_MSG_TEMPLATE, truststoreFile));
+        }
+        return createTypedTruststore(truststoreFile, truststorePasswordPath);
+    }
+
+    private static Truststore createTypedTruststore(File truststoreFile, String truststorePasswordPath)
+        throws KeystoreInstanceException, PasswordReaderException, LoadTruststoreException, TruststoreFileFactoryException {
+        String extension = ExtensionResolver.get(truststoreFile);
+        switch (extension) {
+            case JKS_EXTENSION:
+                return JavaTruststoreFactory.create(truststoreFile, truststorePasswordPath, JKS_TYPE);
+            case P12_EXTENSION:
+                return JavaTruststoreFactory.create(truststoreFile, truststorePasswordPath, PKCS12_TYPE);
+            case PEM_EXTENSION:
+                return new PemTruststore(truststoreFile);
+            default:
+                throw new TruststoreFileFactoryException(
+                    String.format(UNKNOWN_TRUSTSTORE_TYPE_MSG_TEMPLATE, extension));
+        }
+    }
+
+}
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/CertificateWithAlias.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/CertificateWithAlias.java
index decc3977..990a1c66 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/CertificateWithAlias.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/CertificateWithAlias.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider.entry;
+package org.onap.oom.truststoremerger.merger.model.certificate;
 
 import java.security.cert.Certificate;
 
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/CertificateWithAliasFactory.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/CertificateWithAliasFactory.java
index 0889650e..ce3c0c47 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/CertificateWithAliasFactory.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/CertificateWithAliasFactory.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider.entry;
+package org.onap.oom.truststoremerger.merger.model.certificate;
 
 import java.security.cert.Certificate;
 
diff --git a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/PemAliasGenerator.java b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/PemAliasGenerator.java
index 56faa1f6..b812fcb3 100644
--- a/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/certification/file/provider/entry/PemAliasGenerator.java
+++ b/trustStoreMerger/src/main/java/org/onap/oom/truststoremerger/merger/model/certificate/PemAliasGenerator.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider.entry;
+package org.onap.oom.truststoremerger.merger.model.certificate;
 
 
 import java.util.concurrent.atomic.AtomicInteger;
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststoreTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststoreTest.java
deleted file mode 100644
index eccf36bc..00000000
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/JavaTruststoreTest.java
+++ /dev/null
@@ -1,116 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file.model;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.onap.oom.truststoremerger.api.CertificateConstants.X_509_CERTIFICATE;
-
-import java.io.IOException;
-import java.security.cert.Certificate;
-import java.util.List;
-import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.Test;
-import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.TestCertificateProvider;
-
-
-class JavaTruststoreTest {
-    public static final int FIRST_ELEMENT = 0;
-    private static final int EXPECTED_ONE = 1;
-    public static final int EXPECTED_THREE = 3;
-
-    @Test
-    void jksTruststoreShouldReadCertificatesFromFile() throws ExitableException {
-
-        //given
-        JavaTruststore jksTruststoreFile = TestCertificateProvider.getSampleJksTruststoreFile();
-
-        //when
-        List<CertificateWithAlias> certificates = jksTruststoreFile.getCertificates();
-        Certificate certificate = certificates.get(FIRST_ELEMENT).getCertificate();
-
-        //then
-        assertThat(certificates).hasSize(EXPECTED_ONE);
-        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
-    }
-
-    @Test
-    void jksTruststoreShouldAddDifferentCertificates() throws Exception {
-
-        //given
-        JavaTruststore jksTruststore = TestCertificateProvider.createTmpJksTruststoreFileWithUniqAlias();
-        List<CertificateWithAlias> p12certificates = TestCertificateProvider.getSampleP12Truststore()
-            .getCertificates();
-        List<CertificateWithAlias> pemCertificates = TestCertificateProvider.getSamplePemTruststoreFile()
-            .getCertificates();
-
-        //when
-        jksTruststore.addCertificate(p12certificates);
-        jksTruststore.addCertificate(pemCertificates);
-
-        //then
-        assertThat(jksTruststore.getCertificates()).hasSize(EXPECTED_THREE);
-
-    }
-
-    @Test
-    void p12TruststoreShouldReadCertificatesFromFile() throws ExitableException {
-        //given
-        JavaTruststore p12Truststore = TestCertificateProvider.getSampleP12Truststore();
-
-        //when
-        List<CertificateWithAlias> certificatesWithAliases = p12Truststore.getCertificates();
-        Certificate certificate = certificatesWithAliases.get(FIRST_ELEMENT).getCertificate();
-
-        //then
-        assertThat(certificatesWithAliases).hasSize(EXPECTED_ONE);
-        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
-    }
-
-
-    @Test
-    void p12TruststoreShouldAddDifferentCertificates() throws Exception {
-        //given
-        JavaTruststore p12Truststore = TestCertificateProvider.createTmpP12TruststoreFile();
-        List<CertificateWithAlias> jksTruststoreCertificates = TestCertificateProvider
-            .getSampleJksTruststoreFileWithUniqueAlias()
-            .getCertificates();
-        List<CertificateWithAlias> pemTruststoreCertificates = TestCertificateProvider.getSamplePemTruststoreFile()
-            .getCertificates();
-
-        //when
-        p12Truststore.addCertificate(jksTruststoreCertificates);
-        p12Truststore.addCertificate(pemTruststoreCertificates);
-        p12Truststore.saveFile();
-
-
-        //then
-        JavaTruststore p12TruststoreSaved = TestCertificateProvider.getTmpP12TruststoreFile();
-        assertThat(p12TruststoreSaved.getCertificates()).hasSize(EXPECTED_THREE);
-    }
-
-
-
-    @AfterAll
-    static void removeTemporaryFiles() throws IOException {
-        TestCertificateProvider.removeTemporaryFiles();
-    }
-}
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststoreTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststoreTest.java
deleted file mode 100644
index e7ffa093..00000000
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/PemTruststoreTest.java
+++ /dev/null
@@ -1,149 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.oom.truststoremerger.certification.file.model;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-import static org.onap.oom.truststoremerger.api.CertificateConstants.X_509_CERTIFICATE;
-
-import java.io.IOException;
-import java.security.cert.Certificate;
-import java.security.cert.CertificateEncodingException;
-import java.util.ArrayList;
-import java.util.List;
-import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.Test;
-import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAliasFactory;
-import org.onap.oom.truststoremerger.certification.file.TestCertificateProvider;
-import org.onap.oom.truststoremerger.certification.file.exception.MissingTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreDataOperationException;
-import org.onap.oom.truststoremerger.certification.file.exception.WriteTruststoreFileException;
-
-class PemTruststoreTest {
-
-    public static final int EXPECTED_ONE = 1;
-    public static final int EXPECTED_THREE = 3;
-    public static final int FIRST_ELEMENT = 0;
-
-    private final CertificateWithAliasFactory factory = new CertificateWithAliasFactory();
-
-    @Test
-    void pemTruststoreShouldReadCertificatesFromFile() throws ExitableException {
-
-        //given
-        PemTruststore pemTruststore = TestCertificateProvider.getSamplePemTruststoreFile();
-
-        //when
-        List<CertificateWithAlias> certificates = pemTruststore.getCertificates();
-        Certificate certificate = certificates.get(FIRST_ELEMENT).getCertificate();
-        //then
-
-        assertThat(certificates).hasSize(EXPECTED_ONE);
-        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
-    }
-
-    @Test
-    void pemTruststoreShouldAddDifferentCertificates() throws IOException, ExitableException {
-
-        //given
-        PemTruststore tmpPemTruststoreFile = TestCertificateProvider.createTmpPemTruststoreFile();
-        List<CertificateWithAlias> jksTruststoreCertificates = TestCertificateProvider
-            .getSampleJksTruststoreFileWithUniqueAlias().getCertificates();
-        List<CertificateWithAlias> p12TruststoreCertificates = TestCertificateProvider.getSampleP12Truststore()
-            .getCertificates();
-
-        //when
-        tmpPemTruststoreFile.addCertificate(jksTruststoreCertificates);
-        tmpPemTruststoreFile.addCertificate(p12TruststoreCertificates);
-        tmpPemTruststoreFile.saveFile();
-
-        PemTruststore tmpPemTruststoreSaved = TestCertificateProvider.getTmpPemTruststoreFile();
-        List<CertificateWithAlias> addedCertificates = tmpPemTruststoreSaved.getCertificates();
-        Certificate certificate = addedCertificates.get(FIRST_ELEMENT).getCertificate();
-
-        //then
-        assertThat(addedCertificates).hasSize(EXPECTED_THREE);
-        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
-
-    }
-
-    @Test
-    void privateKeyIsSkippedWhileReadingCertificates() throws ExitableException {
-        //given
-        PemTruststore pemTruststore = TestCertificateProvider.getPemWithPrivateKeyTruststoreFile();
-
-        //when
-        List<CertificateWithAlias> certificate = pemTruststore.getCertificates();
-        //then
-
-        assertThat(certificate).hasSize(EXPECTED_ONE);
-    }
-
-    @Test
-    void shouldThrowExceptionWhenCannotSaveFile() throws IOException, ExitableException {
-        //given
-        PemTruststore tmpPemTruststoreFile = TestCertificateProvider.createTmpPemTruststoreFile();
-        List<CertificateWithAlias> pemTruststoreCertificates =
-            TestCertificateProvider.getSamplePemTruststoreFile().getCertificates();
-        //when
-        tmpPemTruststoreFile.addCertificate(pemTruststoreCertificates);
-        tmpPemTruststoreFile.getFile().setWritable(false);
-        //then
-        assertThatExceptionOfType(WriteTruststoreFileException.class)
-            .isThrownBy(tmpPemTruststoreFile::saveFile);
-
-    }
-
-    @Test
-    void shouldThrowExceptionWhenFileNotContainsCertificate() throws IOException {
-        //given
-        PemTruststore tmpPemTruststoreFile = TestCertificateProvider.createEmptyTmpPemTruststoreFile();
-        //when//then
-        assertThatExceptionOfType(MissingTruststoreException.class)
-            .isThrownBy(tmpPemTruststoreFile::getCertificates);
-    }
-
-    @Test
-    void shouldThrowExceptionWhenCannotConvertCertificateToPem() throws Exception {
-        //given
-        PemTruststore pemTruststore = TestCertificateProvider.createTmpPemTruststoreFile();
-        Certificate certificate = mock(Certificate.class);
-
-        when(certificate.getEncoded()).thenThrow(new CertificateEncodingException());
-
-        List<CertificateWithAlias> certificatesWithAliases = new ArrayList<>();
-        certificatesWithAliases.add(factory.createPemCertificate(certificate));
-        pemTruststore.addCertificate(certificatesWithAliases);
-
-        //when //then
-        assertThatExceptionOfType(TruststoreDataOperationException.class)
-            .isThrownBy(pemTruststore::saveFile);
-    }
-
-    @AfterAll
-    static void removeTemporaryFiles() throws IOException {
-        TestCertificateProvider.removeTemporaryFiles();
-    }
-
-}
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/TruststoreFilesListProviderTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/TruststoreFilesListProviderTest.java
deleted file mode 100644
index 0dadcfef..00000000
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/TruststoreFilesListProviderTest.java
+++ /dev/null
@@ -1,87 +0,0 @@
-/*============LICENSE_START=======================================================
- * oom-truststore-merger
- * ================================================================================
- * Copyright (C) 2020 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-
-package org.onap.oom.truststoremerger.certification.file.provider;
-
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import org.onap.oom.truststoremerger.certification.file.TruststoreFileFactory;
-import org.onap.oom.truststoremerger.certification.file.TruststoreFilesListProvider;
-import org.onap.oom.truststoremerger.certification.file.model.JavaTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.PemTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.Truststore;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-
-import java.io.File;
-import java.util.Arrays;
-import java.util.List;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreFileFactoryException;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-class TruststoreFilesListProviderTest {
-
-    private static final String TRUSTSTORE_JKS_PATH = "src/test/resources/truststore-jks.jks";
-    private static final String TRUSTSTORE_JKS_PASS_PATH = "src/test/resources/truststore-jks.pass";
-    private static final String TRUSTSTORE_P12_PATH = "src/test/resources/truststore-p12.p12";
-    private static final String TRUSTSTORE_P12_PASS_PATH = "src/test/resources/truststore-p12.pass";
-    private static final String TRUSTSTORE_PEM_PATH = "src/test/resources/truststore.pem";
-    private static final String EMPTY_PASS_PATH = "";
-
-    private TruststoreFilesListProvider truststoreFilesListProvider;
-
-    @BeforeEach
-    void setUp() {
-        TruststoreFileFactory truststoreFileFactory = new TruststoreFileFactory(new FileManager(), new PasswordReader());
-        truststoreFilesListProvider = new TruststoreFilesListProvider(truststoreFileFactory);
-    }
-
-    @Test
-    void shouldReturnTruststoreFilesList()
-        throws TruststoreFileFactoryException, PasswordReaderException, LoadTruststoreException, KeystoreInstanceException {
-        List<String> truststorePaths = Arrays.asList(TRUSTSTORE_JKS_PATH, TRUSTSTORE_P12_PATH, TRUSTSTORE_PEM_PATH);
-        List<String> truststorePasswordPaths = Arrays.asList(TRUSTSTORE_JKS_PASS_PATH, TRUSTSTORE_P12_PASS_PATH, EMPTY_PASS_PATH);
-        List<Truststore> truststoreFilesList = truststoreFilesListProvider.getTruststoreFilesList(truststorePaths, truststorePasswordPaths);
-        assertThat(truststoreFilesList.size()).isEqualTo(3);
-        assertCorrectJksTruststore(truststoreFilesList.get(0), TRUSTSTORE_JKS_PATH);
-        assertCorrectP12Truststore(truststoreFilesList.get(1), TRUSTSTORE_P12_PATH);
-        assertCorrectPemTruststore(truststoreFilesList.get(2), TRUSTSTORE_PEM_PATH);
-    }
-
-    private void assertCorrectJksTruststore(Truststore truststore, String truststorePath) {
-        assertCorrectTypeAndTruststorePath(truststore, truststorePath, JavaTruststore.class);
-    }
-
-    private void assertCorrectP12Truststore(Truststore truststore, String truststorePath) {
-        assertCorrectTypeAndTruststorePath(truststore, truststorePath, JavaTruststore.class);
-    }
-
-    private void assertCorrectPemTruststore(Truststore truststore, String truststorePath) {
-        assertCorrectTypeAndTruststorePath(truststore, truststorePath, PemTruststore.class);
-    }
-
-    private void assertCorrectTypeAndTruststorePath(Truststore truststore, String truststorePath, Class<?> truststoreType) {
-        assertThat(truststore).isInstanceOf(truststoreType);
-        assertThat(truststore.getFile()).isEqualTo(new File(truststorePath));
-    }
-
-}
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/TruststoreTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/BackupCreatorTest.java
index eea1f9c7..b81eb36e 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/model/TruststoreTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/BackupCreatorTest.java
@@ -17,44 +17,35 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.model;
+package org.onap.oom.truststoremerger.common;
+
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.File;
 import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Paths;
-import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
-import org.onap.oom.truststoremerger.certification.file.exception.CreateBackupException;
-import org.onap.oom.truststoremerger.certification.file.provider.PemCertificateController;
-
-import static org.assertj.core.api.Assertions.assertThat;
+import org.onap.oom.truststoremerger.merger.exception.CreateBackupException;
+import org.onap.oom.truststoremerger.merger.model.TestCertificateProvider;
 
-class TruststoreTest {
-
-    private static final String PEM_FILE_PATH = "src/test/resources/truststore.pem";
-    private static final String PEM_BACKUP_FILE_PATH = "src/test/resources/truststore.pem.bak";
-    private static final String BACKUP_EXTENSION = ".bak";
+public class BackupCreatorTest {
 
+    public static final String BAK_EXTENSION = ".bak";
 
     @Test
-    void createBackupShouldCreateFileWithExtension() throws CreateBackupException {
+    void shouldCreateBackupProvidedFile() throws CreateBackupException {
         //given
-        File pemFile = new File(PEM_FILE_PATH);
-        Truststore truststore = new PemTruststore(pemFile, new PemCertificateController(pemFile));
+        File fileToBackup = new File(TestCertificateProvider.PEM_FILE_PATH);
+        String backupFilePath = fileToBackup.getPath() + BAK_EXTENSION;
         //when
-        truststore.createBackup();
-
+        BackupCreator.createBackup(fileToBackup);
         //then
-        File backupFile = new File(PEM_BACKUP_FILE_PATH);
-        assertThat(backupFile.getName().endsWith(BACKUP_EXTENSION)).isTrue();
-        assertThat(backupFile.isFile()).isTrue();
+        assertThat(fileToBackup.equals(new File(backupFilePath)));
     }
 
-
-    @AfterAll
-    static void removeBackupFile() throws IOException {
-        Files.deleteIfExists(Paths.get(PEM_BACKUP_FILE_PATH));
+    @AfterEach
+    void removeTemporaryFiles() throws IOException {
+        TestCertificateProvider.removeTemporaryFiles();
     }
 
 }
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/FileManagerTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/ExtensionResolverTest.java
index c649ba68..e59a7671 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/FileManagerTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/ExtensionResolverTest.java
@@ -18,7 +18,7 @@
  */
 
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.common;
 
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
@@ -27,9 +27,7 @@ import java.io.File;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-class FileManagerTest {
-
-    private FileManager fileManager = new FileManager();
+class ExtensionResolverTest {
 
     @ParameterizedTest
     @CsvSource(value = {
@@ -40,7 +38,7 @@ class FileManagerTest {
         "opt/app/truststore:''",
     }, delimiter = ':')
     void shouldReturnCorrectExtension(String filePath, String expectedExtension) {
-        String extension = fileManager.getExtension(new File(filePath));
+        String extension = ExtensionResolver.get(new File(filePath));
         assertThat(extension).isEqualTo(expectedExtension);
     }
 
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/PasswordReaderTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/PasswordReaderTest.java
index 40eda4dd..a43951bd 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/PasswordReaderTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/common/PasswordReaderTest.java
@@ -17,12 +17,12 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.common;
 
 import org.junit.jupiter.api.Test;
 
 import java.io.File;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -31,15 +31,13 @@ class PasswordReaderTest {
 
     @Test
     void shouldReturnCorrectPasswordFromFile() throws PasswordReaderException {
-        PasswordReader passwordReader = new PasswordReader();
-        String fileData = passwordReader.readPassword(new File("src/test/resources/truststore-jks.pass"));
+        String fileData = PasswordReader.readPassword(new File("src/test/resources/truststore-jks.pass"));
         assertThat(fileData).isEqualTo("EOyuFbuYDyq_EhpboM72RHua");
     }
 
     @Test
     void shouldThrowExceptionForNonExistingFile() {
-        PasswordReader passwordReader = new PasswordReader();
         assertThatExceptionOfType(PasswordReaderException.class)
-                .isThrownBy(() -> passwordReader.readPassword(new File("src/test/resources/non-esisting-file.pass")));
+                .isThrownBy(() -> PasswordReader.readPassword(new File("src/test/resources/non-esisting-file.pass")));
     }
 }
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/TruststoreFilesProviderTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/TruststoreFilesProviderTest.java
new file mode 100644
index 00000000..9fc00a42
--- /dev/null
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/TruststoreFilesProviderTest.java
@@ -0,0 +1,63 @@
+/*============LICENSE_START=======================================================
+ * oom-truststore-merger
+ * ================================================================================
+ * Copyright (C) 2020 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+
+package org.onap.oom.truststoremerger.merger;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreFileFactoryException;
+import org.onap.oom.truststoremerger.merger.model.Truststore;
+import org.onap.oom.truststoremerger.merger.model.TruststoreFactory;
+
+class TruststoreFilesProviderTest {
+
+    private static final String TRUSTSTORE_JKS_PATH = "src/test/resources/truststore-jks.jks";
+    private static final String TRUSTSTORE_JKS_PASS_PATH = "src/test/resources/truststore-jks.pass";
+    private static final String TRUSTSTORE_P12_PATH = "src/test/resources/truststore-p12.p12";
+    private static final String TRUSTSTORE_P12_PASS_PATH = "src/test/resources/truststore-p12.pass";
+    private static final String TRUSTSTORE_PEM_PATH = "src/test/resources/truststore.pem";
+    private static final String EMPTY_PASS_PATH = "";
+
+    @Test
+    void shouldReturnTruststoreFilesList()
+        throws TruststoreFileFactoryException, PasswordReaderException, LoadTruststoreException, KeystoreInstanceException {
+        //given
+        List<String> truststorePaths = Arrays.asList(TRUSTSTORE_JKS_PATH, TRUSTSTORE_P12_PATH, TRUSTSTORE_PEM_PATH);
+        List<String> truststorePasswordPaths = Arrays
+            .asList(TRUSTSTORE_JKS_PASS_PATH, TRUSTSTORE_P12_PASS_PATH, EMPTY_PASS_PATH);
+
+        //when
+        List<Truststore> truststoreFilesList = TruststoreFilesProvider
+            .getTruststoreFiles(truststorePaths, truststorePasswordPaths);
+
+        //then
+        assertThat(truststoreFilesList.size()).isEqualTo(3);
+        TruststoreFactory.create(TRUSTSTORE_JKS_PATH, TRUSTSTORE_JKS_PASS_PATH);
+        TruststoreFactory.create(TRUSTSTORE_P12_PATH, TRUSTSTORE_P12_PASS_PATH);
+        TruststoreFactory.create(TRUSTSTORE_PEM_PATH, EMPTY_PASS_PATH);
+    }
+
+}
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/JavaCertificateStoreControllerTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/JavaTruststoreTest.java
index 8ee77ef2..99b8e623 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/JavaCertificateStoreControllerTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/JavaTruststoreTest.java
@@ -17,43 +17,40 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
 
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.onap.oom.truststoremerger.certification.file.TestCertificateProvider.getSampleJksTruststoreFile;
 
 import java.util.List;
 import org.junit.jupiter.api.Test;
 import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.TestCertificateProvider;
-import org.onap.oom.truststoremerger.certification.file.exception.AliasConflictException;
-import org.onap.oom.truststoremerger.certification.file.exception.MissingTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.model.JavaTruststore;
-
-class JavaCertificateStoreControllerTest {
+import org.onap.oom.truststoremerger.merger.exception.AliasConflictException;
+import org.onap.oom.truststoremerger.merger.exception.MissingTruststoreException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
 
+class JavaTruststoreTest {
 
     @Test
     void throwExceptionWhenAliasConflictDetected() throws Exception {
         //given
-        JavaTruststore p12Truststore = TestCertificateProvider.getSampleP12Truststore();
-        List<CertificateWithAlias> jksTruststoreCertificates = getSampleJksTruststoreFile().getCertificates();
+        Truststore p12Truststore = TestCertificateProvider.getSampleP12Truststore();
+
+        List<CertificateWithAlias> certificateFromJks = TestCertificateProvider
+            .getSampleJksTruststoreFile().getCertificates();
 
         //when //then
         assertThatExceptionOfType(AliasConflictException.class)
-            .isThrownBy(() -> p12Truststore.addCertificate(jksTruststoreCertificates));
+            .isThrownBy(() -> p12Truststore.addCertificates(certificateFromJks));
     }
 
-
     @Test
     void throwExceptionWhenFileNotContainsTruststoreEntry() throws ExitableException {
         //given
-        JavaTruststore p12Truststore = TestCertificateProvider.getSampleP12Keystore();
+        Truststore p12Truststore = TestCertificateProvider.getSampleP12Keystore();
 
         //when//then
         assertThatExceptionOfType(MissingTruststoreException.class)
-            .isThrownBy(p12Truststore::getCertificates);
+            .isThrownBy(() -> p12Truststore.getCertificates());
     }
 
 }
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/PemCertificateControllerTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/PemTruststoreTest.java
index 080fcca3..505a6826 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/PemCertificateControllerTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/PemTruststoreTest.java
@@ -17,50 +17,70 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.mockito.Mockito.mock;
 
 import java.io.File;
 import java.io.IOException;
+import java.security.KeyStore;
+import java.security.KeyStoreSpi;
 import java.security.cert.Certificate;
 import java.util.List;
 import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 import org.onap.oom.truststoremerger.api.ExitableException;
-import org.onap.oom.truststoremerger.certification.file.provider.entry.CertificateWithAlias;
-import org.onap.oom.truststoremerger.certification.file.TestCertificateProvider;
-import org.onap.oom.truststoremerger.certification.file.exception.MissingTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreDataOperationException;
-import org.onap.oom.truststoremerger.certification.file.model.PemTruststore;
+import org.onap.oom.truststoremerger.merger.exception.MissingTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreDataOperationException;
+import org.onap.oom.truststoremerger.merger.exception.WriteTruststoreFileException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
 
-class PemCertificateControllerTest {
+class PemTruststoreTest {
+
+    private static final int EXPECTED_ONE = 1;
 
     @Test
-    void getNotEmptyCertificateListShouldThrowExceptionWhenFileNotContainsCertificate() {
+    void getCertificatesShouldThrowExceptionWhenFileNotContainsCertificate() {
         //given
-        File emptyPemFile = TestCertificateProvider.getEmptyPemTruststoreFile().getFile();
-        PemCertificateController pemCertificateController = new PemCertificateController(emptyPemFile);
+        File emptyPemFile = TestCertificateProvider.getEmptyPemFile();
+        PemTruststore pemCertificate = new PemTruststore(emptyPemFile);
         //when//then
         assertThatExceptionOfType(MissingTruststoreException.class)
-            .isThrownBy(pemCertificateController::getNotEmptyCertificateList);
+            .isThrownBy(pemCertificate::getCertificates);
+    }
+
+    @Test
+    void shouldThrowExceptionWhenCannotSaveFile() {
+        //given
+        KeyStoreSpi keyStoreSpi = mock(KeyStoreSpi.class);
+        KeyStore keyStore = new KeyStore(keyStoreSpi, null, "") {
+        };
+        File pemFile = TestCertificateProvider.getEmptyPemFile();
+        pemFile.setWritable(false);
+        PemTruststore pem = new PemTruststore(pemFile);
+
+        //when. then
+        assertThatExceptionOfType(WriteTruststoreFileException.class)
+            .isThrownBy(pem::saveFile);
     }
 
     @Test
     void transformToStringInPemFormatShouldCorrectlyTransform() throws ExitableException, IOException {
         //given
-        PemTruststore pemTruststore = TestCertificateProvider.getSamplePemTruststoreFile();
+        Truststore pemTruststore = TestCertificateProvider.getSamplePemTruststoreFile();
+
         List<CertificateWithAlias> wrappedCertificates = pemTruststore.getCertificates();
-        File notEmptyPemFile = pemTruststore.getFile();
         List<Certificate> certificateList = unWrapCertificate(wrappedCertificates);
-        PemCertificateController pemCertificateController = new PemCertificateController(notEmptyPemFile);
-        String expected = TestCertificateProvider.getExpectedPemCertificateAsString();
+        File notEmptyPemFile = TestCertificateProvider.getNotEmptyPemFile();
+        PemTruststore pemCertificate = new PemTruststore(notEmptyPemFile);
 
         //when
-        String certificateTransformed = pemCertificateController.transformToStringInPemFormat(certificateList);
+        String certificateTransformed = pemCertificate.transformToStringInPemFormat(certificateList);
 
         //then
+        String expected = TestCertificateProvider.getExpectedPemCertificateAsString();
         assertThat(certificateTransformed).isEqualTo(expected);
     }
 
@@ -68,21 +88,34 @@ class PemCertificateControllerTest {
     void fileNotContainsPemCertificateShouldReturnTrueIfFileNotContainsCertificate()
         throws TruststoreDataOperationException {
         //given
-        File emptyPemFile = TestCertificateProvider.getEmptyPemTruststoreFile().getFile();
-        PemCertificateController pemCertificateController = new PemCertificateController(emptyPemFile);
+        File emptyPemFile = TestCertificateProvider.getEmptyPemFile();
+        PemTruststore pemCertificate = new PemTruststore(emptyPemFile);
         //when//then
-        assertThat(pemCertificateController.isFileWithoutPemCertificate()).isTrue();
+        assertThat(pemCertificate.isFileWithoutPemCertificate()).isTrue();
     }
 
     @Test
     void fileNotContainsPemCertificateShouldReturnFalseIfFileContainsCertificate()
         throws TruststoreDataOperationException {
         //given
-        File notEmptyPemFile = TestCertificateProvider.getSamplePemTruststoreFile().getFile();
-        PemCertificateController pemCertificateController = new PemCertificateController(notEmptyPemFile);
+        File notEmptyPemFile = TestCertificateProvider.getNotEmptyPemFile();
+        PemTruststore pemCertificate = new PemTruststore(notEmptyPemFile);
 
         //when//then
-        assertThat(pemCertificateController.isFileWithoutPemCertificate()).isFalse();
+        assertThat(pemCertificate.isFileWithoutPemCertificate()).isFalse();
+    }
+
+    @Test
+    void privateKeyIsSkippedWhileReadingCertificates() throws ExitableException {
+        //given
+        File pemTruststoreFile = TestCertificateProvider.getPemWithPrivateKeyFile();
+        PemTruststore pemCertificate = new PemTruststore(pemTruststoreFile);
+
+        //when
+        List<CertificateWithAlias> certificate = pemCertificate.getCertificates();
+
+        //then
+        assertThat(certificate).hasSize(EXPECTED_ONE);
     }
 
     private List<Certificate> unWrapCertificate(List<CertificateWithAlias> certificateWithAliases) {
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/TestCertificateProvider.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TestCertificateProvider.java
index b5893230..abd77d19 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/TestCertificateProvider.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TestCertificateProvider.java
@@ -17,7 +17,10 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file;
+package org.onap.oom.truststoremerger.merger.model;
+
+import static org.onap.oom.truststoremerger.api.CertificateConstants.JKS_TYPE;
+import static org.onap.oom.truststoremerger.api.CertificateConstants.PKCS12_TYPE;
 
 import java.io.File;
 import java.io.IOException;
@@ -25,26 +28,22 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-import org.onap.oom.truststoremerger.certification.file.model.JavaTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.PemTruststore;
-import org.onap.oom.truststoremerger.certification.file.provider.JavaCertificateStoreController;
-import org.onap.oom.truststoremerger.certification.file.provider.CertificateStoreControllerFactory;
-import org.onap.oom.truststoremerger.certification.file.provider.PemCertificateController;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
 
-public class TestCertificateProvider {
+public final class TestCertificateProvider {
 
     public static final String SAMPLE_P12_TRUSTSTORE_FILE_PATH = "src/test/resources/truststore-p12.p12";
-    public static final String SAMPLE_P12_TRUSTSTORE_PASSWORD = "88y9v5D8H3SG6bZWRVHDfOAo";
+    public static final String SAMPLE_P12_TRUSTSTORE_PASSWORD_PATH = "src/test/resources/truststore-p12.pass";
     public static final String TMP_P12_TRUSTSTORE_FILE_PATH = "src/test/resources/tmp-truststore-p12.p12";
 
     public static final String SAMPLE_P12_KEYSTORE_FILE_PATH = "src/test/resources/keystore.p12";
-    public static final String SAMPLE_P12_KEYSTORE_PASSWORD = "Foh49MJNYI7S_pEzE9gvUDSu";
+    public static final String SAMPLE_P12_KEYSTORE_PASSWORD_PATH = "src/test/resources/keystore.pass";
 
     public static final String SAMPLE_JKS_TRUSTSTORE_FILE_PATH = "src/test/resources/truststore-jks.jks";
     public static final String SAMPLE_JKS_TRUSTSTORE_UNIQUE_ALIAS_FILE_PATH = "src/test/resources/truststore-jks-uniq.jks";
-    public static final String SAMPLE_JKS_TRUSTSTORE_PASSWORD = "EOyuFbuYDyq_EhpboM72RHua";
+    public static final String SAMPLE_JKS_TRUSTSTORE_PASSWORD_PATH = "src/test/resources/truststore-jks.pass";
     public static final String TMP_JKS_TRUSTSTORE_FILE_PATH = "src/test/resources/tmp-truststore-jks.jks";
 
     public static final String SAMPLE_PEM_TRUSTSTORE_FILE_PATH = "src/test/resources/truststore.pem";
@@ -52,99 +51,95 @@ public class TestCertificateProvider {
     public static final String TMP_PEM_TRUSTSTORE_FILE_PATH = "src/test/resources/tmp-truststore.pem";
     public static final String SAMPLE_PEM_TRUSTSTORE_WITH_PRIVATE_KEY_FILE_PATH = "src/test/resources/truststore-with-private-key.pem";
 
-    private static final CertificateStoreControllerFactory certificateStoreControllerFactory = new CertificateStoreControllerFactory();
+    public static final String PEM_FILE_PATH = "src/test/resources/truststore.pem";
+    public static final String PEM_BACKUP_FILE_PATH = "src/test/resources/truststore.pem.bak";
 
-    public static JavaTruststore getSampleP12Truststore() throws LoadTruststoreException, KeystoreInstanceException {
-        return createP12TruststoreInstance(SAMPLE_P12_TRUSTSTORE_FILE_PATH, SAMPLE_P12_TRUSTSTORE_PASSWORD);
+    private TestCertificateProvider() {
     }
 
-    public static JavaTruststore getSampleP12Keystore() throws LoadTruststoreException, KeystoreInstanceException {
-        return createP12TruststoreInstance(SAMPLE_P12_KEYSTORE_FILE_PATH, SAMPLE_P12_KEYSTORE_PASSWORD);
+    public static Truststore getSampleP12Truststore()
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        return createJavaTruststore(SAMPLE_P12_TRUSTSTORE_FILE_PATH, SAMPLE_P12_TRUSTSTORE_PASSWORD_PATH, PKCS12_TYPE);
     }
 
-    public static JavaTruststore createTmpP12TruststoreFile()
-        throws IOException, LoadTruststoreException, KeystoreInstanceException {
-        copyFile(SAMPLE_P12_TRUSTSTORE_FILE_PATH, TMP_P12_TRUSTSTORE_FILE_PATH);
-        return createP12TruststoreInstance(TMP_P12_TRUSTSTORE_FILE_PATH, SAMPLE_P12_TRUSTSTORE_PASSWORD);
+    public static Truststore getSampleP12Keystore()
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        return createJavaTruststore(SAMPLE_P12_KEYSTORE_FILE_PATH, SAMPLE_P12_KEYSTORE_PASSWORD_PATH, PKCS12_TYPE);
     }
 
-    public static JavaTruststore getTmpP12TruststoreFile() throws LoadTruststoreException, KeystoreInstanceException {
-        return createP12TruststoreInstance(TMP_P12_TRUSTSTORE_FILE_PATH, SAMPLE_P12_TRUSTSTORE_PASSWORD);
-    }
-
-    private static JavaTruststore createP12TruststoreInstance(String filePath, String password)
-        throws LoadTruststoreException, KeystoreInstanceException {
-        File certFile = getFile(filePath);
-        JavaCertificateStoreController storeController = certificateStoreControllerFactory
-            .createLoadedPkcs12CertificateStoreController(certFile, password);
-        return new JavaTruststore(certFile, storeController);
+    public static Truststore createTmpP12TruststoreFile()
+        throws IOException, LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        copyFile(SAMPLE_P12_TRUSTSTORE_FILE_PATH, TMP_P12_TRUSTSTORE_FILE_PATH);
+        return createJavaTruststore(TMP_P12_TRUSTSTORE_FILE_PATH, SAMPLE_P12_TRUSTSTORE_PASSWORD_PATH, PKCS12_TYPE);
     }
 
-    public static PemTruststore getSamplePemTruststoreFile() {
+    public static Truststore getSamplePemTruststoreFile() {
         return getPemTruststoreInstance(SAMPLE_PEM_TRUSTSTORE_FILE_PATH);
     }
 
-    public static PemTruststore getEmptyPemTruststoreFile() {
-        return getPemTruststoreInstance(EMPTY_PEM_TRUSTSTORE_FILE_PATH);
-    }
-
-    public static PemTruststore createEmptyTmpPemTruststoreFile() throws IOException {
+    public static Truststore createEmptyTmpPemTruststoreFile()
+        throws IOException {
         copyFile(EMPTY_PEM_TRUSTSTORE_FILE_PATH, TMP_PEM_TRUSTSTORE_FILE_PATH);
         return getPemTruststoreInstance(TMP_PEM_TRUSTSTORE_FILE_PATH);
     }
 
-    public static PemTruststore createTmpPemTruststoreFile() throws IOException {
+    public static Truststore createTmpPemTruststoreFile()
+        throws IOException {
         copyFile(SAMPLE_PEM_TRUSTSTORE_FILE_PATH, TMP_PEM_TRUSTSTORE_FILE_PATH);
         return getPemTruststoreInstance(TMP_PEM_TRUSTSTORE_FILE_PATH);
     }
 
-    public static PemTruststore getTmpPemTruststoreFile() {
-        return getPemTruststoreInstance(TMP_PEM_TRUSTSTORE_FILE_PATH);
-    }
-
-    public static PemTruststore getPemWithPrivateKeyTruststoreFile() {
-        return getPemTruststoreInstance(SAMPLE_PEM_TRUSTSTORE_WITH_PRIVATE_KEY_FILE_PATH);
-    }
-
     public static String getExpectedPemCertificateAsString() throws IOException {
         Path samplePemFilePath = Paths.get(SAMPLE_PEM_TRUSTSTORE_FILE_PATH);
         return Files.readString(samplePemFilePath);
     }
 
-    public static JavaTruststore getSampleJksTruststoreFile()
-        throws LoadTruststoreException, KeystoreInstanceException {
-        return createJksTruststoreInstance(SAMPLE_JKS_TRUSTSTORE_FILE_PATH, SAMPLE_JKS_TRUSTSTORE_PASSWORD);
+    public static Truststore getSampleJksTruststoreFile()
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        return createJavaTruststore(SAMPLE_JKS_TRUSTSTORE_FILE_PATH, SAMPLE_JKS_TRUSTSTORE_PASSWORD_PATH, JKS_TYPE);
     }
 
-    public static JavaTruststore getSampleJksTruststoreFileWithUniqueAlias()
-        throws LoadTruststoreException, KeystoreInstanceException {
-        return createJksTruststoreInstance(SAMPLE_JKS_TRUSTSTORE_UNIQUE_ALIAS_FILE_PATH,
-            SAMPLE_JKS_TRUSTSTORE_PASSWORD);
+    public static Truststore getSampleJksTruststoreFileWithUniqueAlias()
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        return createJavaTruststore(SAMPLE_JKS_TRUSTSTORE_UNIQUE_ALIAS_FILE_PATH, SAMPLE_JKS_TRUSTSTORE_PASSWORD_PATH,
+            JKS_TYPE);
     }
 
-    public static JavaTruststore createTmpJksTruststoreFileWithUniqAlias()
-        throws IOException, LoadTruststoreException, KeystoreInstanceException {
+    public static Truststore createTmpJksTruststoreFileWithUniqAlias()
+        throws IOException, LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
         copyFile(SAMPLE_JKS_TRUSTSTORE_UNIQUE_ALIAS_FILE_PATH, TMP_JKS_TRUSTSTORE_FILE_PATH);
-        return createJksTruststoreInstance(TMP_JKS_TRUSTSTORE_FILE_PATH, SAMPLE_JKS_TRUSTSTORE_PASSWORD);
+        return createJavaTruststore(TMP_JKS_TRUSTSTORE_FILE_PATH, SAMPLE_JKS_TRUSTSTORE_PASSWORD_PATH, JKS_TYPE);
+    }
+
+    public static File getEmptyPemFile() {
+        return getFile(EMPTY_PEM_TRUSTSTORE_FILE_PATH);
+    }
+
+    public static File getNotEmptyPemFile() {
+        return getFile(SAMPLE_PEM_TRUSTSTORE_FILE_PATH);
+    }
+
+    public static File getPemWithPrivateKeyFile() {
+        return getFile(SAMPLE_PEM_TRUSTSTORE_WITH_PRIVATE_KEY_FILE_PATH);
     }
 
     public static void removeTemporaryFiles() throws IOException {
         Files.deleteIfExists(Paths.get(TMP_PEM_TRUSTSTORE_FILE_PATH));
         Files.deleteIfExists(Paths.get(TMP_JKS_TRUSTSTORE_FILE_PATH));
         Files.deleteIfExists(Paths.get(TMP_P12_TRUSTSTORE_FILE_PATH));
+        Files.deleteIfExists(Paths.get(PEM_BACKUP_FILE_PATH));
     }
 
-    private static JavaTruststore createJksTruststoreInstance(String filePath, String password)
-        throws LoadTruststoreException, KeystoreInstanceException {
+    private static Truststore createJavaTruststore(String filePath, String password, String instanceType)
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
         File certFile = getFile(filePath);
-        JavaCertificateStoreController storeController = certificateStoreControllerFactory
-            .createLoadedJksCertificateStoreController(certFile, password);
-        return new JavaTruststore(certFile, storeController);
+        return JavaTruststoreFactory.create(certFile, password, instanceType);
     }
 
-    private static PemTruststore getPemTruststoreInstance(String tmpPemTruststoreFilePath) {
+    private static Truststore getPemTruststoreInstance(
+        String tmpPemTruststoreFilePath) {
         File file = getFile(tmpPemTruststoreFilePath);
-        return new PemTruststore(file, new PemCertificateController(file));
+        return new PemTruststore(file);
     }
 
     private static void copyFile(String sourcePath, String destPath) throws IOException {
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/TruststoreFactoryTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TruststoreFactoryTest.java
index b2063cc3..eb6c847a 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/TruststoreFactoryTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TruststoreFactoryTest.java
@@ -18,25 +18,18 @@
  */
 
 
-package org.onap.oom.truststoremerger.certification.file.provider;
+package org.onap.oom.truststoremerger.merger.model;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.junit.jupiter.MockitoExtension;
-import org.onap.oom.truststoremerger.certification.file.TruststoreFileFactory;
-import org.onap.oom.truststoremerger.certification.file.model.JavaTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.PemTruststore;
-import org.onap.oom.truststoremerger.certification.file.model.Truststore;
-import org.onap.oom.truststoremerger.certification.file.exception.KeystoreInstanceException;
-import org.onap.oom.truststoremerger.certification.file.exception.LoadTruststoreException;
-
-import java.io.File;
-import org.onap.oom.truststoremerger.certification.file.exception.PasswordReaderException;
-import org.onap.oom.truststoremerger.certification.file.exception.TruststoreFileFactoryException;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreFileFactoryException;
 
 @ExtendWith(MockitoExtension.class)
 class TruststoreFactoryTest {
@@ -50,66 +43,66 @@ class TruststoreFactoryTest {
     private static final String TRUSTSTORE_UNKNOWN_EXTENSION_PATH = "src/test/resources/truststore-jks.unknown";
     private static final String NON_EXISTING_TRUSTSTORE_PATH = "src/test/resources/non-existing-truststore.jks";
 
-    private TruststoreFileFactory truststoreFileFactory;
-
-    @BeforeEach
-    void setUp() {
-        truststoreFileFactory = new TruststoreFileFactory(new FileManager(), new PasswordReader());
-    }
-
     @Test
     void shouldReturnCorrectJksTruststoreForJksFile()
         throws LoadTruststoreException, PasswordReaderException, TruststoreFileFactoryException, KeystoreInstanceException {
-        Truststore truststore = truststoreFileFactory
-                .create(TRUSTSTORE_JKS_PATH, TRUSTSTORE_JKS_PASS_PATH);
-        assertThat(truststore).isInstanceOf(JavaTruststore.class);
-        JavaTruststore jksTruststore = (JavaTruststore) truststore;
-        assertThat(jksTruststore.getFile()).isEqualTo(new File(TRUSTSTORE_JKS_PATH));
+        //given, when
+        Truststore truststore = TruststoreFactory
+            .create(TRUSTSTORE_JKS_PATH, TRUSTSTORE_JKS_PASS_PATH);
+
+        //then
+        assertThat(truststore).isInstanceOf(Truststore.class);
     }
 
     @Test
     void shouldReturnCorrectP12TruststoreForP12File()
         throws LoadTruststoreException, PasswordReaderException, TruststoreFileFactoryException, KeystoreInstanceException {
-        Truststore truststore = truststoreFileFactory
-                .create(TRUSTSTORE_P12_PATH,
-                        TRUSTSTORE_P12_PASS_PATH);
-        assertThat(truststore).isInstanceOf(JavaTruststore.class);
+        //given, when
+        Truststore truststore = TruststoreFactory
+            .create(TRUSTSTORE_P12_PATH, TRUSTSTORE_P12_PASS_PATH);
+
+        //then
+        assertThat(truststore).isInstanceOf(Truststore.class);
     }
 
     @Test
     void shouldReturnCorrectPemTruststoreForPemFile()
         throws LoadTruststoreException, PasswordReaderException, TruststoreFileFactoryException, KeystoreInstanceException {
-        Truststore truststore = truststoreFileFactory
-                .create(TRUSTSTORE_PEM_PATH,
-                        EMPTY_PASS_PATH);
-        assertThat(truststore).isInstanceOf(PemTruststore.class);
+        //given, when
+        Truststore truststore = TruststoreFactory
+            .create(TRUSTSTORE_PEM_PATH,
+                EMPTY_PASS_PATH);
+
+        //then
+        assertThat(truststore).isInstanceOf(Truststore.class);
     }
 
     @Test
     void shouldThrowExceptionForInvalidP12PassPath() {
         assertThatExceptionOfType(PasswordReaderException.class).isThrownBy(
-                () -> truststoreFileFactory.create(TRUSTSTORE_P12_PATH, EMPTY_PASS_PATH)
+            () -> TruststoreFactory.create(TRUSTSTORE_P12_PATH, EMPTY_PASS_PATH)
         );
     }
 
     @Test
     void shouldThrowExceptionForInvalidJksPassPath() {
         assertThatExceptionOfType(PasswordReaderException.class).isThrownBy(
-                () -> truststoreFileFactory.create(TRUSTSTORE_JKS_PATH, EMPTY_PASS_PATH)
+            () -> TruststoreFactory.create(TRUSTSTORE_JKS_PATH, EMPTY_PASS_PATH)
         );
     }
 
     @Test
     void shouldThrowExceptionForUnknownTruststoreExtension() {
         assertThatExceptionOfType(TruststoreFileFactoryException.class).isThrownBy(
-                () -> truststoreFileFactory.create(TRUSTSTORE_UNKNOWN_EXTENSION_PATH, TRUSTSTORE_JKS_PASS_PATH)
+            () -> TruststoreFactory
+                .create(TRUSTSTORE_UNKNOWN_EXTENSION_PATH, TRUSTSTORE_JKS_PASS_PATH)
         );
     }
 
     @Test
     void shouldThrowExceptionForNonExistingTruststoreFile() {
         assertThatExceptionOfType(TruststoreFileFactoryException.class).isThrownBy(
-                () -> truststoreFileFactory.create(NON_EXISTING_TRUSTSTORE_PATH, TRUSTSTORE_JKS_PASS_PATH)
+            () -> TruststoreFactory.create(NON_EXISTING_TRUSTSTORE_PATH, TRUSTSTORE_JKS_PASS_PATH)
         );
     }
 
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TruststoreTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TruststoreTest.java
new file mode 100644
index 00000000..6c294834
--- /dev/null
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/TruststoreTest.java
@@ -0,0 +1,204 @@
+/*============LICENSE_START=======================================================
+ * oom-truststore-merger
+ * ================================================================================
+ * Copyright (C) 2020 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.oom.truststoremerger.merger.model;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.onap.oom.truststoremerger.api.CertificateConstants.X_509_CERTIFICATE;
+
+import java.io.File;
+import java.io.IOException;
+import java.security.cert.Certificate;
+import java.security.cert.CertificateEncodingException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.onap.oom.truststoremerger.api.ExitableException;
+import org.onap.oom.truststoremerger.merger.exception.CreateBackupException;
+import org.onap.oom.truststoremerger.merger.exception.KeystoreInstanceException;
+import org.onap.oom.truststoremerger.merger.exception.LoadTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.MissingTruststoreException;
+import org.onap.oom.truststoremerger.merger.exception.PasswordReaderException;
+import org.onap.oom.truststoremerger.merger.exception.TruststoreDataOperationException;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAlias;
+import org.onap.oom.truststoremerger.merger.model.certificate.CertificateWithAliasFactory;
+
+class TruststoreTest {
+
+    private static final String BACKUP_EXTENSION = ".bak";
+
+    private static final int EXPECTED_ONE = 1;
+    public static final int EXPECTED_THREE = 3;
+    public static final int FIRST_ELEMENT = 0;
+
+    private final CertificateWithAliasFactory factory = new CertificateWithAliasFactory();
+
+    @Test
+    void createBackupShouldCreateFileWithExtension() throws CreateBackupException {
+        //given
+        File pemFile = new File(TestCertificateProvider.PEM_FILE_PATH);
+        Truststore truststore = new PemTruststore(pemFile);
+        //when
+        truststore.createBackup();
+
+        //then
+        File backupFile = new File(TestCertificateProvider.PEM_BACKUP_FILE_PATH);
+        assertThat(backupFile.getName().endsWith(BACKUP_EXTENSION)).isTrue();
+        assertThat(backupFile.isFile()).isTrue();
+    }
+
+    @ParameterizedTest
+    @MethodSource("truststoreProvider")
+    void truststoreShouldReadCertificatesFromFile(Truststore truststore) throws ExitableException {
+        //when
+
+        List<CertificateWithAlias> certificates = truststore.getCertificates();
+        Certificate certificate = certificates.get(FIRST_ELEMENT).getCertificate();
+
+        //then
+        assertThat(certificates).hasSize(EXPECTED_ONE);
+        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
+    }
+
+    @Test
+    void jksTruststoreShouldAddDifferentCertificates() throws Exception {
+        //given
+        Truststore jksTruststore = TestCertificateProvider.createTmpJksTruststoreFileWithUniqAlias();
+
+        List<CertificateWithAlias> certificateFromP12 = TestCertificateProvider.getSampleP12Truststore()
+            .getCertificates();
+
+        List<CertificateWithAlias> certificateFromPem = TestCertificateProvider
+            .getSamplePemTruststoreFile().getCertificates();
+
+        //when
+
+        jksTruststore.addCertificates(certificateFromP12);
+
+        jksTruststore.addCertificates(certificateFromPem);
+
+        jksTruststore.saveFile();
+
+        //then
+
+        assertThat(jksTruststore.getCertificates()).hasSize(EXPECTED_THREE);
+    }
+
+    @Test
+    void p12TruststoreShouldAddDifferentCertificates() throws Exception {
+        //given
+        Truststore p12Truststore = TestCertificateProvider.createTmpP12TruststoreFile();
+
+        List<CertificateWithAlias> certificateFromJks = TestCertificateProvider
+            .getSampleJksTruststoreFileWithUniqueAlias().getCertificates();
+
+        List<CertificateWithAlias> certificateFromPem = TestCertificateProvider
+            .getSamplePemTruststoreFile().getCertificates();
+
+        //when
+
+        p12Truststore.addCertificates(certificateFromJks);
+        p12Truststore.addCertificates(certificateFromPem);
+        p12Truststore.saveFile();
+
+        //then
+
+        assertThat(p12Truststore.getCertificates()).hasSize(EXPECTED_THREE);
+    }
+
+    @Test
+    void pemTruststoreShouldAddDifferentCertificates() throws IOException, ExitableException {
+        //given
+        Truststore pemTruststore = TestCertificateProvider
+            .createTmpPemTruststoreFile();
+
+        List<CertificateWithAlias> certificateFromJks = TestCertificateProvider
+            .getSampleJksTruststoreFileWithUniqueAlias().getCertificates();
+
+        List<CertificateWithAlias> certificateFromP12 = TestCertificateProvider.getSampleP12Truststore()
+            .getCertificates();
+
+        //when
+
+        pemTruststore.addCertificates(certificateFromJks);
+
+        pemTruststore.addCertificates(certificateFromP12);
+
+        pemTruststore.saveFile();
+
+        //then
+
+        List<CertificateWithAlias> addedCertificates = pemTruststore.getCertificates();
+        Certificate certificate = addedCertificates.get(FIRST_ELEMENT).getCertificate();
+
+        assertThat(pemTruststore.getCertificates()).hasSize(EXPECTED_THREE);
+        assertThat(certificate.getType()).isEqualTo(X_509_CERTIFICATE);
+    }
+
+    @Test
+    void shouldThrowExceptionWhenFileNotContainsCertificate() throws IOException {
+        //given
+        Truststore tmpPemTruststoreFile = TestCertificateProvider
+            .createEmptyTmpPemTruststoreFile();
+        //when//then
+        assertThatExceptionOfType(MissingTruststoreException.class)
+            .isThrownBy(() -> tmpPemTruststoreFile.getCertificates());
+    }
+
+    @Test
+    void shouldThrowExceptionWhenCannotConvertCertificateToPem() throws Exception {
+        //given
+        Truststore pemTruststore = TestCertificateProvider.createTmpPemTruststoreFile();
+        Certificate certificate = mock(Certificate.class);
+
+        when(certificate.getEncoded()).thenThrow(new CertificateEncodingException());
+
+        List<CertificateWithAlias> certificateFromPem = new ArrayList<>();
+        certificateFromPem.add(factory.createPemCertificate(certificate));
+
+        pemTruststore.addCertificates(certificateFromPem);
+
+        //when //then
+        assertThatExceptionOfType(TruststoreDataOperationException.class)
+            .isThrownBy(() -> pemTruststore.saveFile());
+    }
+
+    @AfterEach
+    void removeTemporaryFiles() throws IOException {
+        TestCertificateProvider.removeTemporaryFiles();
+    }
+
+    private static Stream<Arguments> truststoreProvider()
+        throws LoadTruststoreException, KeystoreInstanceException, PasswordReaderException {
+        return Stream.of(
+            Arguments.of(TestCertificateProvider.getSampleJksTruststoreFile()),
+            Arguments.of(TestCertificateProvider.getSampleP12Truststore()),
+            Arguments.of(TestCertificateProvider.getSamplePemTruststoreFile())
+        );
+    }
+
+}
diff --git a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/entry/PemAliasGeneratorTest.java b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/certificate/PemAliasGeneratorTest.java
index f05cbc86..4ff3e750 100644
--- a/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/certification/file/provider/entry/PemAliasGeneratorTest.java
+++ b/trustStoreMerger/src/test/java/org/onap/oom/truststoremerger/merger/model/certificate/PemAliasGeneratorTest.java
@@ -17,7 +17,7 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.oom.truststoremerger.certification.file.provider.entry;
+package org.onap.oom.truststoremerger.merger.model.certificate;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
diff --git a/trustStoreMerger/src/test/resources/keystore.pass b/trustStoreMerger/src/test/resources/keystore.pass
new file mode 100644
index 00000000..665ff8e6
--- /dev/null
+++ b/trustStoreMerger/src/test/resources/keystore.pass
@@ -0,0 +1 @@
+Foh49MJNYI7S_pEzE9gvUDSu
\ No newline at end of file