appc-dg-common sonar fixes part 2

Sonar fixes in whole module

Change-Id: I9d2d7f092fc44217c794ea3a4d4b12b1ad641ff0
Issue-ID: APPC-673
Signed-off-by: Jakub Dudycz <jakub.dudycz@nokia.com>

19 files changed, 294 insertions, 251 deletions

diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/AbstractResolver.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/AbstractResolver.java
index 78dd780d4..2f1050fb8 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/AbstractResolver.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/AbstractResolver.java
@@ -32,21 +32,25 @@ import org.onap.appc.rankingframework.RankedAttributesResolver;
 abstract class AbstractResolver {
 
     private static final EELFLogger logger = EELFManager.getInstance().getLogger(AbstractResolver.class);
+    private static final long INTERVAL_MULTIPLIER = 1000L;
 
     private long interval;
-
-    private volatile long lastUpdate = 0l;
+    private volatile long lastUpdate = 0L;
     private volatile boolean isUpdateInProgress = false;
     private volatile RankedAttributesResolver<FlowKey> dgResolver;
 
-    private final ReentrantLock INIT_LOCK = new ReentrantLock();
+    private final ReentrantLock initLock = new ReentrantLock();
 
     AbstractResolver(int interval) {
-        this.interval = interval * 1000l;
+        this.interval = interval * INTERVAL_MULTIPLIER;
     }
 
     private RankedAttributesResolver<FlowKey> createResolver(String resolverType) {
         AbstractResolverDataReader reader = ResolverDataReaderFactory.createResolverDataReader(resolverType);
+
+        if (reader == null) {
+            throw new DataReaderException("Cannot read data since reader is null");
+        }
         return reader.read();
     }
 
@@ -55,29 +59,25 @@ abstract class AbstractResolver {
     }
 
     protected RankedAttributesResolver<FlowKey> resolver(String resolverType) {
-
         /*
          * In general case, the method implementation is non-blocking. The first
          * thread that identifies data expiration will be used to refresh it. In
          * meanwhile, any other thread will get the old instance without waiting
          * for the updated one. The only exception is the very first time when
          * previous instance doesn't exist - in such a cases all the threads
-         * will be waiting on INIT_LOCK while one of them initializes the
+         * will be waiting on initLock while one of them initializes the
          * resolver instance. NOTE: The initialization is intentionally
          * implemented in lazy manner to make sure the bundle is initialized
          * properly on startup regardless whether or not the data is correct.
          * Afterwards, the resolver may be instantiated as many times as needed.
          */
-
         try {
-
             if (dgResolver == null) {
-                INIT_LOCK.lock();
+                initLock.lock();
                 if (dgResolver != null) {
-                    INIT_LOCK.unlock();
+                    initLock.unlock();
                 }
             }
-
             if (!isUpdateInProgress && isExpired()) {
 
                 boolean doUpgrade = false;
@@ -88,30 +88,29 @@ abstract class AbstractResolver {
                         doUpgrade = true;
                     }
                 }
-
                 if (doUpgrade) {
-
                     logger.info("DG resolver configuration data has expired - initiating refresh");
-
-                    try {
-                        RankedAttributesResolver<FlowKey> temp = createResolver(resolverType);
-                        dgResolver = temp;
-                        lastUpdate = System.currentTimeMillis();
-
-                        logger.info("DG resolver configuration data has been refreshed successfully");
-                    } finally {
-                        isUpdateInProgress = false;
-                    }
+                    tryRefreshConfig(resolverType);
                 }
             }
         } finally {
-            if (INIT_LOCK.isHeldByCurrentThread()) {
-                INIT_LOCK.unlock();
+            if (initLock.isHeldByCurrentThread()) {
+                initLock.unlock();
             }
         }
-
         return dgResolver;
     }
 
+    private void tryRefreshConfig(String resolverType) {
+        try {
+            dgResolver = createResolver(resolverType);
+            lastUpdate = System.currentTimeMillis();
+
+            logger.info("DG resolver configuration data has been refreshed successfully");
+        } finally {
+            isUpdateInProgress = false;
+        }
+    }
+
     protected abstract FlowKey resolve(final String... args);
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/Constants.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/Constants.java
index 9009f3c62..1e62dcc66 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/Constants.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/Constants.java
@@ -52,12 +52,31 @@ class Constants {
     public static final String CVAAS_FILE_NAME = "cvaas-file-name";
     public static final String CVAAS_FILE_CONTENT = "cvaas-file-content";
 
+    // DG Resolver Constants
+    public static final String IN_PARAM_VNF_TYPE = "vnfType";
+    public static final String IN_PARAM_VNFC_TYPE = "vnfcType";
+    public static final String IN_PARAM_ACTION = "action";
+    public static final String IN_PARAM_API_VERSION = "api-ver";
+
+    public static final String OUT_PARAM_DG_NAME = "dg_name";
+    public static final String OUT_PARAM_DG_VERSION = "dg_version";
+    public static final String OUT_PARAM_DG_MODULE = "dg_module";
+
+    public static final String TABLE_NAME = "VNFC_DG_MAPPING";
+    public static final String TABLE_COLUMN_VNF_TYPE = "VNF_TYPE";
+    public static final String TABLE_COLUMN_VNFC_TYPE = "VNFC_TYPE";
+    public static final String TABLE_COLUMN_ACTION = "ACTION";
+    public static final String TABLE_COLUMN_API_VERSION = "API_VERSION";
+    public static final String TABLE_COLUMN_DG_NAME = "DG_NAME";
+    public static final String TABLE_COLUMN_DG_VERSION = "DG_VERSION";
+    public static final String TABLE_COLUMN_DG_MODULE = "DG_MODULE";
+
     enum LegacyAttributes {
-        Action("org.onap.appc.action"),
+        ACTION("org.onap.appc.action"),
         VMID("org.onap.appc.vmid"),
-        IdentityURL("org.onap.appc.identity.url"),
-        TenantID("org.onap.appc.tenant.id"),
-        SkipHypervisorCheck("org.onap.appc.skiphypervisorcheck");
+        IDENTITY_URL("org.onap.appc.identity.url"),
+        TENANT_ID("org.onap.appc.tenant.id"),
+        SKIP_HYPERVISOR_CHECK("org.onap.appc.skiphypervisorcheck");
 
         private String value;
 
@@ -70,15 +89,13 @@ class Constants {
         }
     }
 
-    ;
-
     enum LCMAttributes {
-        Action("input.action"),
-        Payload("input.payload"),
+        ACTION("input.action"),
+        PAYLOAD("input.payload"),
         VMID("vm-id"),
-        IdentityURL("identity-url"),
-        TenantID("tenant.id"),
-        SkipHypervisorCheck("skip-hypervisor-check");
+        IDENTITY_URL("identity-url"),
+        TENANT_ID("tenant.id"),
+        SKIP_HYPERVISOR_CHECK("skip-hypervisor-check");
 
         private String value;
 
@@ -90,25 +107,4 @@ class Constants {
             return value;
         }
     }
-
-    ;
-
-    // DG Resolver Constants
-    public static final String IN_PARAM_VNF_TYPE = "vnfType";
-    public static final String IN_PARAM_VNFC_TYPE = "vnfcType";
-    public static final String IN_PARAM_ACTION = "action";
-    public static final String IN_PARAM_API_VERSION = "api-ver";
-
-    public static final String OUT_PARAM_DG_NAME = "dg_name";
-    public static final String OUT_PARAM_DG_VERSION = "dg_version";
-    public static final String OUT_PARAM_DG_MODULE = "dg_module";
-
-    public static final String TABLE_NAME = "VNFC_DG_MAPPING";
-    public static final String TABLE_COLUMN_VNF_TYPE = "VNF_TYPE";
-    public static final String TABLE_COLUMN_VNFC_TYPE = "VNFC_TYPE";
-    public static final String TABLE_COLUMN_ACTION = "ACTION";
-    public static final String TABLE_COLUMN_API_VERSION = "API_VERSION";
-    public static final String TABLE_COLUMN_DG_NAME = "DG_NAME";
-    public static final String TABLE_COLUMN_DG_VERSION = "DG_VERSION";
-    public static final String TABLE_COLUMN_DG_MODULE = "DG_MODULE";
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DCAEReporterPluginImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DCAEReporterPluginImpl.java
index f0e7674ee..c66a54ad4 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DCAEReporterPluginImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DCAEReporterPluginImpl.java
@@ -37,6 +37,9 @@ import org.onap.ccsdk.sli.core.sli.SvcLogicContext;
 
 public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
 
+    private static final String ATTR_API_VERSION = "input.common-header.api-ver";
+    private static final String ATTR_REQUEST_ID = "input.common-header.request-id";
+    private static final String PARAM_EVENT_TOPIC_NAME = "event-topic-name";
     private EventSender eventSender;
 
     public DCAEReporterPluginImpl() {
@@ -54,7 +57,9 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
 
     @Override
     public void report(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
-        String errorDescription, apiVersion, eventId;
+        String errorDescription;
+        String apiVersion;
+        String eventId;
 
         Integer errorCode = readErrorCode(params, ctx);
         errorDescription = params.get(Constants.EVENT_MESSAGE);
@@ -62,13 +67,13 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
         if (StringUtils.isEmpty(errorDescription)) {
             reportLegacy(params, ctx);
         } else {
-            apiVersion = ctx.getAttribute("input.common-header.api-ver");
-            eventId = ctx.getAttribute("input.common-header.request-id");
+            apiVersion = ctx.getAttribute(ATTR_API_VERSION);
+            eventId = ctx.getAttribute(ATTR_REQUEST_ID);
 
             EventMessage eventMessage = new EventMessage(new EventHeader(
                 (new java.util.Date()).toString(), apiVersion, eventId),
                 new EventStatus(errorCode, errorDescription));
-            String eventWriteTopic = params.get("event-topic-name");
+            String eventWriteTopic = params.get(PARAM_EVENT_TOPIC_NAME);
             if (!StringUtils.isEmpty(eventWriteTopic) && eventWriteTopic != null) {
                 eventSender.sendEvent(MessageDestination.DCAE, eventMessage, eventWriteTopic);
             } else {
@@ -93,15 +98,18 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
     @Override
     public void reportSuccess(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
         Integer successReportCode = 500;
-        String successDescription, apiVersion, eventId;
+        String successDescription;
+        String apiVersion;
+        String eventId;
+
         successDescription = params.get(Constants.EVENT_MESSAGE);
 
         if (StringUtils.isEmpty(successDescription)) {
             successDescription = params.get(Constants.DG_OUTPUT_STATUS_MESSAGE);
         }
 
-        apiVersion = ctx.getAttribute("input.common-header.api-ver");
-        eventId = ctx.getAttribute("input.common-header.request-id");
+        apiVersion = ctx.getAttribute(ATTR_API_VERSION);
+        eventId = ctx.getAttribute(ATTR_REQUEST_ID);
 
         if (null == successDescription) {
             successDescription = "Success";
@@ -109,7 +117,7 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
         EventMessage eventMessage = new EventMessage(new EventHeader(
             (new java.util.Date()).toString(), apiVersion, eventId),
             new EventStatus(successReportCode, successDescription));
-        String eventWriteTopic = params.get("event-topic-name");
+        String eventWriteTopic = params.get(PARAM_EVENT_TOPIC_NAME);
         if (!StringUtils.isEmpty(eventWriteTopic) && eventWriteTopic != null) {
             eventSender.sendEvent(MessageDestination.DCAE, eventMessage, eventWriteTopic);
         } else {
@@ -118,18 +126,20 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
     }
 
     private void reportLegacy(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
-        String errorDescription, apiVersion, eventId;
+        String errorDescription;
+        String apiVersion;
+        String eventId;
 
         Integer errorCode = readErrorCode(params, ctx);
         errorDescription = getErrorDescriptionAndAddToCtx(params, ctx);
 
-        apiVersion = ctx.getAttribute("input.common-header.api-ver");
-        eventId = ctx.getAttribute("input.common-header.request-id");
+        apiVersion = ctx.getAttribute(ATTR_API_VERSION);
+        eventId = ctx.getAttribute(ATTR_REQUEST_ID);
 
         EventMessage eventMessage = new EventMessage(new EventHeader(
             (new java.util.Date()).toString(), apiVersion, eventId),
             new EventStatus(errorCode, errorDescription));
-        String eventWriteTopic = params.get("event-topic-name");
+        String eventWriteTopic = params.get(PARAM_EVENT_TOPIC_NAME);
         if (!StringUtils.isEmpty(eventWriteTopic) && eventWriteTopic != null) {
             eventSender.sendEvent(MessageDestination.DCAE, eventMessage, eventWriteTopic);
         } else {
@@ -140,6 +150,7 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
     private String getErrorDescriptionAndAddToCtx(Map<String, String> params, SvcLogicContext ctx) {
         String errorDescription;
         errorDescription = params.get(Constants.DG_OUTPUT_STATUS_MESSAGE);
+
         if (StringUtils.isEmpty(errorDescription)) {
             errorDescription = ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE);
         }
@@ -162,5 +173,4 @@ public class DCAEReporterPluginImpl implements DCAEReporterPlugin {
             ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE, errorDescriptionFromCtx + " | " + errorDescription);
         }
     }
-
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DataReaderException.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DataReaderException.java
index f12a83b04..742ff123d 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DataReaderException.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DataReaderException.java
@@ -29,4 +29,8 @@ public class DataReaderException extends RuntimeException {
     public DataReaderException(Throwable cause) {
         super(cause);
     }
+
+    public DataReaderException(String message) {
+        super(message);
+    }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverException.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverException.java
new file mode 100644
index 000000000..260fd7752
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverException.java
@@ -0,0 +1,12 @@
+package org.onap.appc.dg.common.impl;
+
+public class DgResolverException extends RuntimeException{
+
+    public DgResolverException(String message) {
+        super(message);
+    }
+
+    public DgResolverException(Throwable cause) {
+        super(cause);
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverPluginImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverPluginImpl.java
index 5b98dd941..ade2cbb16 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverPluginImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/DgResolverPluginImpl.java
@@ -33,33 +33,40 @@ import org.onap.ccsdk.sli.core.sli.SvcLogicContext;
 
 public class DgResolverPluginImpl implements DgResolverPlugin {
 
+    private static final String PARAM_DG_RESOLUTION_TYPE = "DGResolutionType";
+
     @Override
     public void resolveDg(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
 
-        String DGName, DGVersion, DGModule = null;
+        String dgName;
+        String dgVersion;
+        String dgModule;
+
         String prefix = params.containsKey("prefix") ? params.get("prefix") + "." : "";
-        AbstractResolver resolver = ResolverFactory.createResolver(params.get("DGResolutionType"));
+        AbstractResolver resolver = ResolverFactory.createResolver(params.get(PARAM_DG_RESOLUTION_TYPE));
         FlowKey flowKey = null;
         try {
+            if (resolver == null)
+                throw new DgResolverException("Couldn't create resolver of type: " + PARAM_DG_RESOLUTION_TYPE);
 
-            if (params.get("DGResolutionType").equalsIgnoreCase("VNFC")) {
+            if ("VNFC".equalsIgnoreCase(params.get(PARAM_DG_RESOLUTION_TYPE))) {
                 flowKey = resolver
                     .resolve(params.get(Constants.IN_PARAM_ACTION), params.get(Constants.IN_PARAM_VNF_TYPE),
                         params.get(Constants.IN_PARAM_VNFC_TYPE), params.get(Constants.IN_PARAM_API_VERSION));
-            } else if (params.get("DGResolutionType").equalsIgnoreCase("VNF")) {
+            } else if ("VNF".equalsIgnoreCase(params.get(PARAM_DG_RESOLUTION_TYPE))) {
                 flowKey = resolver
                     .resolve(params.get(Constants.IN_PARAM_ACTION), params.get(Constants.IN_PARAM_VNF_TYPE),
                         params.get("vnfVersion"), params.get(Constants.IN_PARAM_API_VERSION));
             }
             if (flowKey != null) {
-                DGName = flowKey.name();
-                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_NAME, DGName);
-                DGVersion = flowKey.version();
-                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_VERSION, DGVersion);
-                DGModule = flowKey.module();
-                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_MODULE, DGModule);
+                dgName = flowKey.name();
+                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_NAME, dgName);
+                dgVersion = flowKey.version();
+                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_VERSION, dgVersion);
+                dgModule = flowKey.module();
+                ctx.setAttribute(prefix + Constants.OUT_PARAM_DG_MODULE, dgModule);
             } else {
-                throw new RuntimeException(params.get("DGResolutionType") + " DG not found for vnf type :" + params
+                throw new DgResolverException(params.get(PARAM_DG_RESOLUTION_TYPE) + " DG not found for vnf type :" + params
                     .get(Constants.IN_PARAM_VNF_TYPE)
                     + " vnfc type : " + params.get(Constants.IN_PARAM_VNFC_TYPE)
                     + " action : " + params.get(Constants.IN_PARAM_ACTION)
@@ -69,7 +76,7 @@ public class DgResolverPluginImpl implements DgResolverPlugin {
             String msg = EELFResourceManager
                 .format(Msg.FAILURE_RETRIEVE_VNFC_DG, params.get(Constants.IN_PARAM_VNFC_TYPE), e.getMessage());
             ctx.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, msg);
-            throw new RuntimeException(e);
+            throw new DgResolverException(e);
         }
     }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/IntermediateMessageSenderImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/IntermediateMessageSenderImpl.java
index d9caf8f19..4010fd758 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/IntermediateMessageSenderImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/IntermediateMessageSenderImpl.java
@@ -29,6 +29,7 @@ import com.att.eelf.configuration.EELFLogger;
 import com.att.eelf.configuration.EELFManager;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Properties;
@@ -47,12 +48,12 @@ import org.osgi.framework.ServiceReference;
 
 public class IntermediateMessageSenderImpl implements IntermediateMessageSender {
 
+    private final EELFLogger logger = EELFManager.getInstance().getLogger(IntermediateMessageSenderImpl.class);
 
-    private Producer producer;
-
-    private Configuration configuration;
+    private static final String PARAM_MESSAGE = "message";
+    private static final String ATTR_REQUEST_ID = "input.common-header.request-id";
 
-    private final EELFLogger logger = EELFManager.getInstance().getLogger(IntermediateMessageSenderImpl.class);
+    private Producer producer;
 
     private static final String STATUS = "STATUS";
     private static final String FAILURE = "FAILURE";
@@ -63,8 +64,7 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
     private static final String MSO = "MSO";
 
     public void init() {
-        configuration = ConfigurationFactory.getConfiguration();
-        Properties properties = configuration.getProperties();
+        Properties properties =  ConfigurationFactory.getConfiguration().getProperties();
 
         String writeTopic = properties.getProperty("appc.LCM.topic.write");
         String apiKey = properties.getProperty("appc.LCM.client.key");
@@ -76,9 +76,7 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
 
         Set<String> pool = new HashSet<>();
         if (!StringUtils.isEmpty(hostNames)) {
-            for (String name : hostNames.split(",")) {
-                pool.add(name);
-            }
+            pool.addAll(Arrays.asList(hostNames.split(",")));
         }
 
         BundleContext ctx = FrameworkUtil.getBundle(IntermediateMessageSenderImpl.class).getBundleContext();
@@ -111,11 +109,11 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
 
     private void validateInputs(Map<String, String> params, SvcLogicContext context) throws APPCException {
         String code = params.get("code");
-        String message = params.get("message");
+        String message = params.get(PARAM_MESSAGE);
         if (StringUtils.isEmpty(code) || StringUtils.isEmpty(message)) {
             throw new APPCException("code or message is empty");
         }
-        String requestId = context.getAttribute("input.common-header.request-id");
+        String requestId = context.getAttribute(ATTR_REQUEST_ID);
         if (StringUtils.isEmpty(requestId)) {
             throw new APPCException("requestId is empty");
         }
@@ -145,7 +143,7 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
     }
 
     private String getCorrelationId(SvcLogicContext context) {
-        String requestId = context.getAttribute("input.common-header.request-id");
+        String requestId = context.getAttribute(ATTR_REQUEST_ID);
         String subRequestId = context.getAttribute("input.common-header.sub-request-id");
         return requestId + (StringUtils.isEmpty(subRequestId) ? "" : ("-" + subRequestId));
     }
@@ -154,7 +152,7 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
         ObjectMapper objectMapper = new ObjectMapper();
         ObjectNode status = objectMapper.createObjectNode();
         status.put("code", params.get("code"));
-        status.put("message", params.get("message"));
+        status.put(PARAM_MESSAGE, params.get(PARAM_MESSAGE));
         return status;
     }
 
@@ -164,7 +162,7 @@ public class IntermediateMessageSenderImpl implements IntermediateMessageSender
         commonHeader.put("api-ver", context.getAttribute("input.common-header.api-ver"));
         commonHeader.put("timestamp", context.getAttribute("input.common-header.timestamp"));
         commonHeader.put("originator-id", context.getAttribute("input.common-header.originator-id"));
-        commonHeader.put("request-id", context.getAttribute("input.common-header.request-id"));
+        commonHeader.put("request-id", context.getAttribute(ATTR_REQUEST_ID));
         commonHeader.put("sub-request-id", context.getAttribute("input.common-header.sub-request-id"));
         return commonHeader;
     }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/JsonDgUtilImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/JsonDgUtilImpl.java
index 3d43dc1cd..16488e242 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/JsonDgUtilImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/JsonDgUtilImpl.java
@@ -47,11 +47,8 @@ public class JsonDgUtilImpl implements JsonDgUtil {
 
     private static final EELFLogger logger = EELFManager.getInstance().getLogger(JsonDgUtilImpl.class);
 
-    private static final ThreadLocal<SimpleDateFormat> DATE_TIME_PARSER_THREAD_LOCAL = new ThreadLocal<SimpleDateFormat>() {
-        protected SimpleDateFormat initialValue() {
-            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-        }
-    };
+    private static final ThreadLocal<SimpleDateFormat> DATE_TIME_PARSER_THREAD_LOCAL = ThreadLocal
+        .withInitial(() -> new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
 
     @Override
     public void flatAndAddToContext(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
@@ -69,11 +66,7 @@ public class JsonDgUtilImpl implements JsonDgUtil {
             }
             if (!StringUtils.isEmpty(payload)) {
                 Map<String, String> flatMap = JsonUtil.convertJsonStringToFlatMap(payload);
-                if (flatMap != null && flatMap.size() > 0) {
-                    for (Map.Entry<String, String> entry : flatMap.entrySet()) {
-                        ctx.setAttribute(entry.getKey(), entry.getValue());
-                    }
-                }
+                tryUpdateContext(ctx, flatMap);
             } else {
                 logger.warn("input payload param value is empty (\"\") or null");
             }
@@ -85,6 +78,14 @@ public class JsonDgUtilImpl implements JsonDgUtil {
         }
     }
 
+    private void tryUpdateContext(SvcLogicContext ctx, Map<String, String> flatMap) {
+        if (flatMap != null && flatMap.size() > 0) {
+            for (Map.Entry<String, String> entry : flatMap.entrySet()) {
+                ctx.setAttribute(entry.getKey(), entry.getValue());
+            }
+        }
+    }
+
     @Override
     public void generateOutputPayloadFromContext(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
         if (logger.isTraceEnabled()) {
@@ -95,30 +96,12 @@ public class JsonDgUtilImpl implements JsonDgUtil {
         try {
             Set<String> keys = ctx.getAttributeKeySet();
             ObjectMapper objectMapper = new ObjectMapper();
-            ObjectNode JsonNode = objectMapper.createObjectNode();
+            ObjectNode jsonNode = objectMapper.createObjectNode();
             for (String key : keys) {
-                if (key.startsWith(Constants.OUTPUT_PAYLOAD + ".")) {
-                    String objkey = key.replaceFirst(Constants.OUTPUT_PAYLOAD + ".", "");
-                    if (objkey.contains("[") && objkey.contains("]")) {
-                        ArrayNode arrayNode;
-                        String arrayKey = objkey.substring(0, objkey.indexOf('['));
-                        int arrayIndex = Integer
-                            .parseInt(objkey.substring(objkey.indexOf('[') + 1, objkey.indexOf(']')));
-                        if (JsonNode.has(arrayKey)) {
-                            arrayNode = (ArrayNode) JsonNode.get(arrayKey);
-                            arrayNode.insert(arrayIndex, ctx.getAttribute(key));
-                        } else {
-                            arrayNode = objectMapper.createArrayNode();
-                            arrayNode.insert(arrayIndex, ctx.getAttribute(key));
-                            JsonNode.put(arrayKey, arrayNode);
-                        }
-                    } else {
-                        JsonNode.put(objkey, ctx.getAttribute(key));
-                    }
-                }
+                updateJsonNode(ctx, objectMapper, jsonNode, key);
             }
-            if (JsonNode.size() > 0) {
-                ctx.setAttribute(Constants.OUTPUT_PAYLOAD, objectMapper.writeValueAsString(JsonNode));
+            if (jsonNode.size() > 0) {
+                ctx.setAttribute(Constants.OUTPUT_PAYLOAD, objectMapper.writeValueAsString(jsonNode));
             }
         } catch (Exception e) {
             logger.error(e.toString());
@@ -128,6 +111,28 @@ public class JsonDgUtilImpl implements JsonDgUtil {
 
     }
 
+    private void updateJsonNode(SvcLogicContext ctx, ObjectMapper objectMapper, ObjectNode jsonNode, String key) {
+        if (key.startsWith(Constants.OUTPUT_PAYLOAD + ".")) {
+            String objkey = key.replaceFirst(Constants.OUTPUT_PAYLOAD + ".", "");
+            if (objkey.contains("[") && objkey.contains("]")) {
+                ArrayNode arrayNode;
+                String arrayKey = objkey.substring(0, objkey.indexOf('['));
+                int arrayIndex = Integer
+                    .parseInt(objkey.substring(objkey.indexOf('[') + 1, objkey.indexOf(']')));
+                if (jsonNode.has(arrayKey)) {
+                    arrayNode = (ArrayNode) jsonNode.get(arrayKey);
+                    arrayNode.insert(arrayIndex, ctx.getAttribute(key));
+                } else {
+                    arrayNode = objectMapper.createArrayNode();
+                    arrayNode.insert(arrayIndex, ctx.getAttribute(key));
+                    jsonNode.put(arrayKey, arrayNode);
+                }
+            } else {
+                jsonNode.put(objkey, ctx.getAttribute(key));
+            }
+        }
+    }
+
     @Override
     public void cvaasFileNameAndFileContentToContext(Map<String, String> params, SvcLogicContext ctx)
         throws APPCException {
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/LegacyUtilImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/LegacyUtilImpl.java
index 400dadb34..8da7d5d92 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/LegacyUtilImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/LegacyUtilImpl.java
@@ -35,31 +35,33 @@ public class LegacyUtilImpl implements LegacyUtil {
 
     @Override
     public void prepareRequest(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
-        ctx.setAttribute(Constants.LegacyAttributes.Action.getValue(),
-            ctx.getAttribute(Constants.LCMAttributes.Action.getValue()).toLowerCase());
+        ctx.setAttribute(Constants.LegacyAttributes.ACTION.getValue(),
+            ctx.getAttribute(Constants.LCMAttributes.ACTION.getValue()).toLowerCase());
 
-        String payloadStr = ctx.getAttribute(Constants.LCMAttributes.Payload.getValue());
+        String payloadStr = ctx.getAttribute(Constants.LCMAttributes.PAYLOAD.getValue());
         Map<String, String> payloads = JSONUtil.extractPlainValues(payloadStr,
-            Constants.LCMAttributes.VMID.getValue(), Constants.LCMAttributes.IdentityURL.getValue(),
-            Constants.LCMAttributes.TenantID.getValue(),
-            Constants.LCMAttributes.SkipHypervisorCheck.getValue());
+            Constants.LCMAttributes.VMID.getValue(), Constants.LCMAttributes.IDENTITY_URL.getValue(),
+            Constants.LCMAttributes.TENANT_ID.getValue(),
+            Constants.LCMAttributes.SKIP_HYPERVISOR_CHECK.getValue());
 
         ctx.setAttribute(Constants.LegacyAttributes.VMID.getValue(),
             payloads.get(Constants.LCMAttributes.VMID.getValue()));
-        ctx.setAttribute(Constants.LegacyAttributes.IdentityURL.getValue(),
-            payloads.get(Constants.LCMAttributes.IdentityURL.getValue()));
-        ctx.setAttribute(Constants.LegacyAttributes.TenantID.getValue(),
-            payloads.get(Constants.LCMAttributes.TenantID.getValue()));
-        ctx.setAttribute(Constants.LegacyAttributes.SkipHypervisorCheck.getValue(),
-            payloads.get(Constants.LCMAttributes.SkipHypervisorCheck.getValue()));
+        ctx.setAttribute(Constants.LegacyAttributes.IDENTITY_URL.getValue(),
+            payloads.get(Constants.LCMAttributes.IDENTITY_URL.getValue()));
+        ctx.setAttribute(Constants.LegacyAttributes.TENANT_ID.getValue(),
+            payloads.get(Constants.LCMAttributes.TENANT_ID.getValue()));
+        ctx.setAttribute(Constants.LegacyAttributes.SKIP_HYPERVISOR_CHECK.getValue(),
+            payloads.get(Constants.LCMAttributes.SKIP_HYPERVISOR_CHECK.getValue()));
 
     }
 
     @Override
     public void convertPositiveResponse(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
+        /*TODO implement this method*/
     }
 
     @Override
     public void convertNegativeResponse(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
+        /*TODO implement this method*/
     }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/OutputMessagePluginImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/OutputMessagePluginImpl.java
index cd385c9d2..f6e24b5d9 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/OutputMessagePluginImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/OutputMessagePluginImpl.java
@@ -35,7 +35,8 @@ public class OutputMessagePluginImpl implements OutputMessagePlugin {
 
     @Override
     public void outputMessageBuilder(Map<String, String> params, SvcLogicContext ctx) throws APPCException {
-        String errorDescription, eventDescription;
+        String errorDescription;
+        String eventDescription;
 
         //making output.status.message
         errorDescription = params.get(Constants.ATTRIBUTE_ERROR_MESSAGE);
@@ -52,23 +53,22 @@ public class OutputMessagePluginImpl implements OutputMessagePlugin {
         }
     }
 
-    public static void addToContextIfNotContains(String errorDescription, String eventDescription,
+    private static void addToContextIfNotContains(String errorDescription, String eventDescription,
         SvcLogicContext ctx) {
         if (!isEmpty(errorDescription)) {
-            if (isEmpty(ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE))) {
-                ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE, errorDescription);
-            } else if (!ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE).contains(errorDescription)) {
-                ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE,
-                    ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE) + " | " + errorDescription);
-            }
+            updateContext(errorDescription, ctx);
         }
         if (!isEmpty(eventDescription)) {
-            if (isEmpty(ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE))) {
-                ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE, eventDescription);
-            } else if (!ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE).contains(eventDescription)) {
-                ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE,
-                    ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE) + " | " + eventDescription);
-            }
+            updateContext(eventDescription, ctx);
+        }
+    }
+
+    private static void updateContext(String eventDescription, SvcLogicContext ctx) {
+        if (isEmpty(ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE))) {
+            ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE, eventDescription);
+        } else if (!ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE).contains(eventDescription)) {
+            ctx.setAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE,
+                ctx.getAttribute(Constants.DG_OUTPUT_STATUS_MESSAGE) + " | " + eventDescription);
         }
     }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverDataReaderFactory.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverDataReaderFactory.java
index 15e4ab681..c71614766 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverDataReaderFactory.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverDataReaderFactory.java
@@ -31,20 +31,24 @@ public class ResolverDataReaderFactory {
 
     private static final Configuration configuration = ConfigurationFactory.getConfiguration();
 
-    private static class ReferenceHolder {
-
-        private static final AbstractResolverDataReader VNFC_RESOLVER_DATA_READER = new VNFCResolverDataReader();
-
-        private static final AbstractResolverDataReader VNF_RESOLVER_DATA_READER = new VNFResolverDataReader();
-    }
+    private ResolverDataReaderFactory() {}
 
     public static AbstractResolverDataReader createResolverDataReader(String resolverType) {
-        if (resolverType.equalsIgnoreCase("VNF")) {
+        if ("VNF".equalsIgnoreCase(resolverType)) {
             return ReferenceHolder.VNF_RESOLVER_DATA_READER;
-        } else if (resolverType.equalsIgnoreCase("VNFC")) {
+        } else if ("VNFC".equalsIgnoreCase(resolverType)) {
             return ReferenceHolder.VNFC_RESOLVER_DATA_READER;
         } else {
             return null;
         }
     }
+
+    private static class ReferenceHolder {
+
+        private static final AbstractResolverDataReader VNFC_RESOLVER_DATA_READER = new VNFCResolverDataReader();
+
+        private static final AbstractResolverDataReader VNF_RESOLVER_DATA_READER = new VNFResolverDataReader();
+
+        private ReferenceHolder() {}
+    }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverFactory.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverFactory.java
index be71dae8d..6474836dc 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverFactory.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/ResolverFactory.java
@@ -31,21 +31,25 @@ public class ResolverFactory {
 
     private static final Configuration configuration = ConfigurationFactory.getConfiguration();
 
-    private static class ReferenceHolder {
-
-        private static final AbstractResolver VNFC_RESOLVER = new VNFCResolver(
-            configuration.getIntegerProperty("org.onap.appc.workflow.resolver.refresh_interval", 300));
-        private static final AbstractResolver VNF_RESOLVER = new VNFResolver(
-            configuration.getIntegerProperty("org.onap.appc.workflow.resolver.refresh_interval", 300));
-    }
+    private ResolverFactory() {}
 
     public static AbstractResolver createResolver(String resolverType) {
-        if (resolverType.equalsIgnoreCase("VNF")) {
+        if ("VNF".equalsIgnoreCase(resolverType)) {
             return ReferenceHolder.VNF_RESOLVER;
-        } else if (resolverType.equalsIgnoreCase("VNFC")) {
+        } else if ("VNFC".equalsIgnoreCase(resolverType)) {
             return ReferenceHolder.VNFC_RESOLVER;
         } else {
             return null;
         }
     }
+
+    private static class ReferenceHolder {
+
+        private static final AbstractResolver VNFC_RESOLVER = new VNFCResolver(
+            configuration.getIntegerProperty("org.onap.appc.workflow.resolver.refresh_interval", 300));
+        private static final AbstractResolver VNF_RESOLVER = new VNFResolver(
+            configuration.getIntegerProperty("org.onap.appc.workflow.resolver.refresh_interval", 300));
+
+        private ReferenceHolder(){}
+    }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFCResolver.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFCResolver.java
index a6b5e656f..5766e8de2 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFCResolver.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFCResolver.java
@@ -24,6 +24,7 @@
 
 package org.onap.appc.dg.common.impl;
 
+import java.util.Arrays;
 import org.onap.appc.rankingframework.RankedAttributesContext;
 
 
@@ -36,34 +37,28 @@ public class VNFCResolver extends AbstractResolver {
     @Override
     protected FlowKey resolve(String... args) {
         if (args.length != 4) {
-            throw new IllegalStateException(args.toString());
+            throw new IllegalStateException(Arrays.toString(args));
         }
         return resolve(args[0], args[1], args[2], args[3]);
     }
 
-    protected FlowKey resolve(final String action, final String vnfType, final String vnfcType,
+    private FlowKey resolve(final String action, final String vnfType, final String vnfcType,
         final String apiVersion) {
-        RankedAttributesContext context = new RankedAttributesContext() {
-            @Override
-            public Object getAttributeValue(String name) {
-                switch (name) {
-                    case "action":
-                        return action;
-                    case "api_version":
-                        return apiVersion;
-                    case "vnf_type":
-                        return vnfType;
-                    case "vnfc_type":
-                        return vnfcType;
-                    default:
-                        throw new IllegalStateException(name);
-                }
+        RankedAttributesContext context = name -> {
+            switch (name) {
+                case "action":
+                    return action;
+                case "api_version":
+                    return apiVersion;
+                case "vnf_type":
+                    return vnfType;
+                case "vnfc_type":
+                    return vnfcType;
+                default:
+                    throw new IllegalStateException(name);
             }
         };
-
-        FlowKey wfKey = resolver("VNFC").resolve(context);
-
-        return wfKey;
+        return resolver("VNFC").resolve(context);
     }
 }
 
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFResolver.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFResolver.java
index 10d4fffc3..37033703f 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFResolver.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VNFResolver.java
@@ -37,29 +37,22 @@ public class VNFResolver extends AbstractResolver {
         return resolve(args[0], args[1], args[2], args[3]);
     }
 
-
-    protected FlowKey resolve(final String action, final String vnfType, final String vnfVersion,
+    private FlowKey resolve(final String action, final String vnfType, final String vnfVersion,
         final String apiVersion) {
-        RankedAttributesContext context = new RankedAttributesContext() {
-            @Override
-            public Object getAttributeValue(String name) {
-                switch (name) {
-                    case "action":
-                        return action;
-                    case "api_version":
-                        return apiVersion;
-                    case "vnf_type":
-                        return vnfType;
-                    case "vnf_version":
-                        return vnfVersion;
-                    default:
-                        throw new IllegalStateException(name);
-                }
+        RankedAttributesContext context = name -> {
+            switch (name) {
+                case "action":
+                    return action;
+                case "api_version":
+                    return apiVersion;
+                case "vnf_type":
+                    return vnfType;
+                case "vnf_version":
+                    return vnfVersion;
+                default:
+                    throw new IllegalStateException(name);
             }
         };
-
-        FlowKey wfKey = resolver("VNF").resolve(context);
-
-        return wfKey;
+        return resolver("VNF").resolve(context);
     }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionFlowImpl.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionFlowImpl.java
index fe7545d0f..7be6f098c 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionFlowImpl.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionFlowImpl.java
@@ -84,23 +84,24 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
             DependencyManager dependencyManager = DependencyModelFactory.createDependencyManager();
             dependencyModel = dependencyManager.getVnfcDependencyModel(
                 modelIdentifier, DependencyTypes.findByString(dependencyType));
+
         } catch (DependencyModelNotFound e) {
             String msg = EELFResourceManager
-                .format(Msg.DEPENDENCY_MODEL_NOT_FOUND, params.get(Constants.VNF_TYPE), e.getMessage());
-            logger.error(msg);
+                .format(Msg.DEPENDENCY_MODEL_NOT_FOUND, params.get(Constants.VNF_TYPE));
+            logger.error(msg, e);
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, msg);
             context.setAttribute("dependencyModelFound", "false");
             return;
         } catch (InvalidDependencyModelException e) {
             String msg = EELFResourceManager
-                .format(Msg.INVALID_DEPENDENCY_MODEL, params.get(Constants.VNF_TYPE), e.getMessage());
-            logger.error(msg);
+                .format(Msg.INVALID_DEPENDENCY_MODEL, params.get(Constants.VNF_TYPE));
+            logger.error(msg, e);
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, msg);
-            throw new RuntimeException(e.getMessage(), e);
+            throw new VnfExecutionInternalException(e);
         } catch (APPCException e) {
             logger.error(e.getMessage());
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, e.getMessage());
-            throw new RuntimeException(e.getMessage(), e);
+            throw new VnfExecutionInternalException(e);
         } catch (RuntimeException e) {
             logger.error(e.getMessage());
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, e.getMessage());
@@ -112,19 +113,16 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
             logger.debug("Dependency Model = " + dependencyModel);
         }
         logger.info("Building Inventory Model from DG context");
-        InventoryModel inventoryModel = null;
+        InventoryModel inventoryModel;
         try {
             inventoryModel = readInventoryModel(context);
         } catch (APPCException e) {
             logger.error(e.getMessage());
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, e.getMessage());
-            throw new RuntimeException(e.getMessage(), e);
+            throw new VnfExecutionInternalException(e);
         }
         if (logger.isDebugEnabled()) {
             logger.debug("Inventory Model = " + inventoryModel);
-        }
-
-        if (logger.isDebugEnabled()) {
             logger.debug("Validating inventory model with dependency model");
         }
         try {
@@ -132,7 +130,7 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
         } catch (APPCException e) {
             logger.error(e.getMessage());
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, e.getMessage());
-            throw new RuntimeException(e.getMessage(), e);
+            throw new VnfExecutionInternalException(e);
         }
         logger.info("Creating flow builder");
         FlowBuilder flowBuilder = FlowBuilderFactory.getInstance().getFlowBuilder(
@@ -147,7 +145,7 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
                 .format(Msg.INVALID_DEPENDENCY_MODEL, params.get(Constants.VNF_TYPE), e.getMessage());
             logger.error(msg);
             context.setAttribute(Constants.ATTRIBUTE_ERROR_MESSAGE, msg);
-            throw new RuntimeException(e.getMessage(), e);
+            throw new VnfExecutionInternalException(e);
         }
 
         // remove VNFCs from the flow model where vserver list is empty
@@ -172,15 +170,19 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
             throw new APPCException("Flow Strategy from the input : " + flowStrategy + " is invalid.");
         }
         String vnfType = params.get(Constants.VNF_TYPE);
-        if (vnfType == null || vnfType.length() == 0) {
+        if (nullOrEmpty(vnfType)) {
             throw new APPCException("Vnf Type is not passed in the input");
         }
         String vnfVersion = params.get(Constants.VNF_VERION);
-        if (vnfVersion == null || vnfVersion.length() == 0) {
+        if (nullOrEmpty(vnfVersion)) {
             throw new APPCException("Vnf Version not found");
         }
     }
 
+    private boolean nullOrEmpty(String vnfType) {
+        return vnfType == null || vnfType.isEmpty();
+    }
+
     private void logContext(SvcLogicContext context) {
         for (String key : context.getAttributeKeySet()) {
             logger.debug(key + " = " + context.getAttribute(key) + "\n");
@@ -219,7 +221,7 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
             String vnfcName = context.getAttribute(VNF_VNFC + i + "].name");
             String vnfcType = context.getAttribute(VNF_VNFC + i + "].type");
             String vmCountStr = context.getAttribute(VNF_VNFC + i + "].vm_count");
-            if (vnfcType == null || vnfcType.length() == 0) {
+            if (nullOrEmpty(vnfcType)) {
                 throw new APPCException("Could not retrieve VNFC Type from DG Context for vnf.vnfc[" + i + "].type");
             }
             Integer vmCount = Integer.parseInt(vmCountStr);
@@ -288,7 +290,7 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
         } else {
             Set<String> difference = new HashSet<>(dependencyModelMandatoryVnfcSet);
             difference.removeAll(inventoryModelVnfcsSet);
-            if (difference.size() > 0) {
+            if (!difference.isEmpty()) {
                 logger.error("Inventory model is missing following mandatory vnfc type(s): " + difference);
                 throw new APPCException("Inventory model is missing following mandatory vnfc type(s): " + difference);
             }
@@ -301,15 +303,18 @@ public class VnfExecutionFlowImpl implements VnfExecutionFlow {
             Iterator<Vnfc> vnfcIterator = flowIterator.next().iterator();
             while (vnfcIterator.hasNext()) {
                 Vnfc vnfc = vnfcIterator.next();
-                if (vnfc.getVserverList().size() == 0) {
-                    if (logger.isDebugEnabled()) {
-                        logger.debug("No vservers present for Vnfc type: " + vnfc.getVnfcType()
-                            + ". Hence, removing it from the flow model.");
-                    }
-                    vnfcIterator.remove();
-                }
+                tryRemoveInterator(vnfcIterator, vnfc);
             }
         }
     }
 
+    private void tryRemoveInterator(Iterator<Vnfc> vnfcIterator, Vnfc vnfc) {
+        if (vnfc.getVserverList().isEmpty()) {
+            if (logger.isDebugEnabled()) {
+                logger.debug("No vservers present for Vnfc type: " + vnfc.getVnfcType()
+                    + ". Hence, removing it from the flow model.");
+            }
+            vnfcIterator.remove();
+        }
+    }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionInternalException.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionInternalException.java
new file mode 100644
index 000000000..2b5ab7ab6
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/impl/VnfExecutionInternalException.java
@@ -0,0 +1,8 @@
+package org.onap.appc.dg.common.impl;
+
+public class VnfExecutionInternalException extends RuntimeException{
+
+    public VnfExecutionInternalException(Throwable cause) {
+        super(cause);
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/objects/ConnectionDetails.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/objects/ConnectionDetails.java
index 40f5cba11..e5e5c001e 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/objects/ConnectionDetails.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/objects/ConnectionDetails.java
@@ -63,5 +63,4 @@ public class ConnectionDetails {
     public void setPassword(String password) {
         this.password = password;
     }
-
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JAXBUtil.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JAXBUtil.java
index 38012b1bd..7f3cf3927 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JAXBUtil.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JAXBUtil.java
@@ -36,6 +36,8 @@ import java.io.InputStreamReader;
 
 public class JAXBUtil {
 
+    private JAXBUtil() {}
+
     public static <T> T toObject(String xml, Class<T> type) throws JAXBException {
 
         //create JAXB context
@@ -48,6 +50,5 @@ public class JAXBUtil {
         BufferedReader reader = new BufferedReader(new InputStreamReader(xmlInputStream));
 
         return type.cast(unmarshaller.unmarshal(reader));
-
     }
 }
diff --git a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JSONUtil.java b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JSONUtil.java
index 388295a7d..6b77d6cd1 100644
--- a/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JSONUtil.java
+++ b/appc-dg/appc-dg-shared/appc-dg-common/src/main/java/org/onap/appc/dg/common/utils/JSONUtil.java
@@ -29,6 +29,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 
 import java.io.IOException;
 import java.io.Reader;
+import java.io.UncheckedIOException;
 import java.util.*;
 
 
@@ -36,12 +37,14 @@ public class JSONUtil {
 
     private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
 
+    private JSONUtil() {}
+
     public static <T> T fromJson(String json, Class<T> clazz) {
 
         try {
             return OBJECT_MAPPER.readValue(json, clazz);
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new UncheckedIOException(e);
         }
     }
 
@@ -50,7 +53,7 @@ public class JSONUtil {
         try {
             return OBJECT_MAPPER.readValue(reader, clazz);
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new UncheckedIOException(e);
         }
     }
 
@@ -59,25 +62,23 @@ public class JSONUtil {
         try {
             return OBJECT_MAPPER.writeValueAsString(object);
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new UncheckedIOException(e);
         }
     }
 
-    public static Map<String,String> extractPlainValues(String json, String ... names) {
-        if (null == names) return Collections.emptyMap();
-        Map<String,String> values = new HashMap<>();
+    public static Map<String, String> extractPlainValues(String json, String... names) {
+        if (null == names) {
+            return Collections.emptyMap();
+        }
+        Map<String, String> values = new HashMap<>();
         try {
             final JsonNode jsonNode = OBJECT_MAPPER.readTree(json);
             for (String name : names) {
                 values.put(name, jsonNode.path(name).asText());
             }
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new UncheckedIOException(e);
         }
         return values;
     }
-
-
-
-
 }