Fix sonars in server-pool

Addressed the following sonars in feature-server-pool:
- re-interrupt after catching an InterruptException
- reduce cognitive complexity
- cognitive complexity
- not enough arguments for logger message
- use UnaryOperator instead of Function
- update static fields via static methods
- too many break/continue in for-loop

Also fixed some Eclipse warnings:
- add parameter to generic types
- useless assignments
- newInstance() has been deprecated
- close streams

Issue-ID: POLICY-2616
Change-Id: Ibf6c20e6c2a7eb8c60e1b38f388d86a0f9b8804b
Signed-off-by: Jim Hahn <jrh3@att.com>

8 files changed, 473 insertions, 345 deletions

diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Bucket.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Bucket.java
index b82f2e1d..6241a297 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Bucket.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Bucket.java
@@ -360,63 +360,31 @@ public class Bucket {
 
                     case OWNER_NULL:
                         // <OWNER_NULL> -- owner UUID should be set to 'null'
-                        if (bucket.getOwner() != null) {
-                            logger.info("Bucket {} owner: {}->null",
-                                        index, bucket.getOwner());
-                            bucketChanges = true;
-                            synchronized (bucket) {
-                                bucket.setOwner(null);
-                                bucket.setState(null);
-                            }
-                        }
+                        bucketChanges = nullifyOwner(index, bucket, bucketChanges);
                         break;
 
                     case PRIMARY_BACKUP_UPDATE:
                         // <PRIMARY_BACKUP_UPDATE> <primary-backup-uuid> --
                         // primary backup UUID specified
-                        Server newPrimaryBackup =
-                            Server.getServer(Util.readUuid(dis));
-                        if (bucket.primaryBackup != newPrimaryBackup) {
-                            logger.info("Bucket {} primary backup: {}->{}", index,
-                                        bucket.primaryBackup, newPrimaryBackup);
-                            bucketChanges = true;
-                            bucket.primaryBackup = newPrimaryBackup;
-                        }
+                        bucketChanges = updatePrimaryBackup(dis, index, bucket, bucketChanges);
                         break;
 
                     case PRIMARY_BACKUP_NULL:
                         // <PRIMARY_BACKUP_NULL> --
                         // primary backup should be set to 'null'
-                        if (bucket.primaryBackup != null) {
-                            logger.info("Bucket {} primary backup: {}->null",
-                                        index, bucket.primaryBackup);
-                            bucketChanges = true;
-                            bucket.primaryBackup = null;
-                        }
+                        bucketChanges = nullifyPrimaryBackup(index, bucket, bucketChanges);
                         break;
 
                     case SECONDARY_BACKUP_UPDATE:
                         // <SECONDARY_BACKUP_UPDATE> <secondary-backup-uuid> --
                         // secondary backup UUID specified
-                        Server newSecondaryBackup =
-                            Server.getServer(Util.readUuid(dis));
-                        if (bucket.secondaryBackup != newSecondaryBackup) {
-                            logger.info("Bucket {} secondary backup: {}->{}", index,
-                                        bucket.secondaryBackup, newSecondaryBackup);
-                            bucketChanges = true;
-                            bucket.secondaryBackup = newSecondaryBackup;
-                        }
+                        bucketChanges = updateSecondaryBackup(dis, index, bucket, bucketChanges);
                         break;
 
                     case SECONDARY_BACKUP_NULL:
                         // <SECONDARY_BACKUP_NULL> --
                         // secondary backup should be set to 'null'
-                        if (bucket.secondaryBackup != null) {
-                            logger.info("Bucket {} secondary backup: {}->null",
-                                        index, bucket.secondaryBackup);
-                            bucketChanges = true;
-                            bucket.secondaryBackup = null;
-                        }
+                        bucketChanges = nullifySecondaryBackup(index, bucket, bucketChanges);
                         break;
 
                     default:
@@ -433,6 +401,65 @@ public class Bucket {
         return changes;
     }
 
+    private static boolean nullifyOwner(int index, Bucket bucket, boolean bucketChanges) {
+        if (bucket.getOwner() != null) {
+            logger.info("Bucket {} owner: {}->null",
+                        index, bucket.getOwner());
+            bucketChanges = true;
+            synchronized (bucket) {
+                bucket.setOwner(null);
+                bucket.setState(null);
+            }
+        }
+        return bucketChanges;
+    }
+
+    private static boolean updatePrimaryBackup(DataInputStream dis, int index, Bucket bucket, boolean bucketChanges)
+                    throws IOException {
+        Server newPrimaryBackup =
+            Server.getServer(Util.readUuid(dis));
+        if (bucket.primaryBackup != newPrimaryBackup) {
+            logger.info("Bucket {} primary backup: {}->{}", index,
+                        bucket.primaryBackup, newPrimaryBackup);
+            bucketChanges = true;
+            bucket.primaryBackup = newPrimaryBackup;
+        }
+        return bucketChanges;
+    }
+
+    private static boolean nullifyPrimaryBackup(int index, Bucket bucket, boolean bucketChanges) {
+        if (bucket.primaryBackup != null) {
+            logger.info("Bucket {} primary backup: {}->null",
+                        index, bucket.primaryBackup);
+            bucketChanges = true;
+            bucket.primaryBackup = null;
+        }
+        return bucketChanges;
+    }
+
+    private static boolean updateSecondaryBackup(DataInputStream dis, int index, Bucket bucket, boolean bucketChanges)
+                    throws IOException {
+        Server newSecondaryBackup =
+            Server.getServer(Util.readUuid(dis));
+        if (bucket.secondaryBackup != newSecondaryBackup) {
+            logger.info("Bucket {} secondary backup: {}->{}", index,
+                        bucket.secondaryBackup, newSecondaryBackup);
+            bucketChanges = true;
+            bucket.secondaryBackup = newSecondaryBackup;
+        }
+        return bucketChanges;
+    }
+
+    private static boolean nullifySecondaryBackup(int index, Bucket bucket, boolean bucketChanges) {
+        if (bucket.secondaryBackup != null) {
+            logger.info("Bucket {} secondary backup: {}->null",
+                        index, bucket.secondaryBackup);
+            bucketChanges = true;
+            bucket.secondaryBackup = null;
+        }
+        return bucketChanges;
+    }
+
     /**
      * Update bucket owner information.
      *
@@ -768,19 +795,7 @@ public class Bucket {
         out.println("Moving bucket " + bucketNumber + " from "
                     + oldHost + " to " + newHost);
 
-        /*
-         * update the owner, and ensure that the primary and secondary backup
-         * remain different from the owner.
-         */
-        bucket.setOwner(newHost);
-        if (newHost == bucket.primaryBackup) {
-            out.println("Moving primary back from " + newHost + " to " + oldHost);
-            bucket.setPrimaryBackup(oldHost);
-        } else if (newHost == bucket.secondaryBackup) {
-            out.println("Moving secondary back from " + newHost
-                        + " to " + oldHost);
-            bucket.setSecondaryBackup(oldHost);
-        }
+        updateOwner(out, bucket, oldHost, newHost);
 
         try {
             /*
@@ -796,6 +811,22 @@ public class Bucket {
         }
     }
 
+    private static void updateOwner(PrintStream out, TestBucket bucket, TestServer oldHost, TestServer newHost) {
+        /*
+         * update the owner, and ensure that the primary and secondary backup
+         * remain different from the owner.
+         */
+        bucket.setOwner(newHost);
+        if (newHost == bucket.primaryBackup) {
+            out.println("Moving primary back from " + newHost + " to " + oldHost);
+            bucket.setPrimaryBackup(oldHost);
+        } else if (newHost == bucket.secondaryBackup) {
+            out.println("Moving secondary back from " + newHost
+                        + " to " + oldHost);
+            bucket.setSecondaryBackup(oldHost);
+        }
+    }
+
     /**
      * This method is called when an incoming /bucket/sessionData message is
      * received from the old owner of the bucket, which presumably means that
@@ -1485,6 +1516,10 @@ public class Bucket {
                 return;
             }
 
+            makeTestBucket(bucketSnapshot);
+        }
+
+        private void makeTestBucket(final Bucket[] bucketSnapshot) {
             /*
              * Now, create a 'TestBucket' table that mirrors the 'Bucket' table.
              * Unlike the standard 'Bucket' and 'Server' tables, the 'TestServer'
@@ -1796,28 +1831,13 @@ public class Bucket {
                 dos.writeShort(i);
 
                 // 'owner' field
-                if (newOwner != null) {
-                    dos.writeByte(OWNER_UPDATE);
-                    Util.writeUuid(dos, newOwner);
-                } else {
-                    dos.writeByte(OWNER_NULL);
-                }
+                writeOwner(dos, newOwner);
 
                 // 'primaryBackup' field
-                if (newPrimary != null) {
-                    dos.writeByte(PRIMARY_BACKUP_UPDATE);
-                    Util.writeUuid(dos, newPrimary);
-                } else {
-                    dos.writeByte(PRIMARY_BACKUP_NULL);
-                }
+                writePrimary(dos, newPrimary);
 
                 // 'secondaryBackup' field
-                if (newSecondary != null) {
-                    dos.writeByte(SECONDARY_BACKUP_UPDATE);
-                    Util.writeUuid(dos, newSecondary);
-                } else {
-                    dos.writeByte(SECONDARY_BACKUP_NULL);
-                }
+                writeSecondary(dos, newSecondary);
 
                 dos.writeByte(END_OF_PARAMETERS_TAG);
             }
@@ -1851,6 +1871,33 @@ public class Bucket {
             MainLoop.queueWork(task);
         }
 
+        private void writeOwner(DataOutputStream dos, UUID newOwner) throws IOException {
+            if (newOwner != null) {
+                dos.writeByte(OWNER_UPDATE);
+                Util.writeUuid(dos, newOwner);
+            } else {
+                dos.writeByte(OWNER_NULL);
+            }
+        }
+
+        private void writePrimary(DataOutputStream dos, UUID newPrimary) throws IOException {
+            if (newPrimary != null) {
+                dos.writeByte(PRIMARY_BACKUP_UPDATE);
+                Util.writeUuid(dos, newPrimary);
+            } else {
+                dos.writeByte(PRIMARY_BACKUP_NULL);
+            }
+        }
+
+        private void writeSecondary(DataOutputStream dos, UUID newSecondary) throws IOException {
+            if (newSecondary != null) {
+                dos.writeByte(SECONDARY_BACKUP_UPDATE);
+                Util.writeUuid(dos, newSecondary);
+            } else {
+                dos.writeByte(SECONDARY_BACKUP_NULL);
+            }
+        }
+
         /**
          * Supports the '/cmd/dumpBuckets' REST message -- this isn't part of
          * a 'rebalance' operation, but it turned out to be a convenient way
@@ -2304,22 +2351,7 @@ public class Bucket {
                         message = messages.poll();
                         if (message == null) {
                             // no messages left
-                            if (state == this) {
-                                if (owner == Server.getThisServer()) {
-                                    // we can now exit the state
-                                    state = null;
-                                    stateChanged();
-                                } else {
-                                    /*
-                                     * We need a grace period before we can
-                                     * remove the 'state' value (this can happen
-                                     * if we receive and process the bulk data
-                                     * before receiving official confirmation
-                                     * that we are owner of the bucket.
-                                     */
-                                    messages = null;
-                                }
-                            }
+                            noMoreMessages();
                             break;
                         }
                     }
@@ -2330,25 +2362,48 @@ public class Bucket {
             }
             if (messages == null) {
                 // this indicates we need to enter a grace period before cleanup,
-                try {
-                    logger.info("{}: entering grace period before terminating",
-                                this);
-                    Thread.sleep(unconfirmedGracePeriod);
-                } catch (InterruptedException e) {
-                    // we are exiting in any case
-                    Thread.currentThread().interrupt();
-                } finally {
-                    synchronized (Bucket.this) {
-                        // Do we need to confirm that we really are the owner?
-                        // What does it mean if we are not?
-                        if (state == this) {
-                            state = null;
-                            stateChanged();
-                        }
+                sleepBeforeCleanup();
+            }
+            logger.info("{}: exiting cleanup state", this);
+        }
+
+        private void noMoreMessages() {
+            if (state == this) {
+                if (owner == Server.getThisServer()) {
+                    // we can now exit the state
+                    state = null;
+                    stateChanged();
+                } else {
+                    /*
+                     * We need a grace period before we can
+                     * remove the 'state' value (this can happen
+                     * if we receive and process the bulk data
+                     * before receiving official confirmation
+                     * that we are owner of the bucket.
+                     */
+                    messages = null;
+                }
+            }
+        }
+
+        private void sleepBeforeCleanup() {
+            try {
+                logger.info("{}: entering grace period before terminating",
+                            this);
+                Thread.sleep(unconfirmedGracePeriod);
+            } catch (InterruptedException e) {
+                // we are exiting in any case
+                Thread.currentThread().interrupt();
+            } finally {
+                synchronized (Bucket.this) {
+                    // Do we need to confirm that we really are the owner?
+                    // What does it mean if we are not?
+                    if (state == this) {
+                        state = null;
+                        stateChanged();
                     }
                 }
             }
-            logger.info("{}: exiting cleanup state", this);
         }
 
         /**
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Discovery.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Discovery.java
index 2d643a34..a53fb4d1 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Discovery.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Discovery.java
@@ -180,14 +180,14 @@ public class Discovery implements TopicListener {
          * same format base64-encoded message that 'Server'
          * instances periodically exchange
          */
-        LinkedHashMap<String, String> map = new LinkedHashMap<>();
         try {
-            map = coder.decode(event, LinkedHashMap.class);
+            @SuppressWarnings("unchecked")
+            LinkedHashMap<String, String> map = coder.decode(event, LinkedHashMap.class);
             String message = map.get("pingData");
             Server.adminRequest(message.getBytes(StandardCharsets.UTF_8));
             logger.info("Received a message, server count={}", Server.getServerCount());
         } catch (CoderException e) {
-            logger.error("Can't decode message: {}", e);
+            logger.error("Can't decode message", e);
         }
     }
 
@@ -332,6 +332,7 @@ public class Discovery implements TopicListener {
                         publisher.send(jsonString);
                     }
                 } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
                     logger.error("Exception in Discovery.Publisher.run():", e);
                     return;
                 } catch (Exception e) {
@@ -340,6 +341,7 @@ public class Discovery implements TopicListener {
                     try {
                         Thread.sleep(15000);
                     } catch (InterruptedException e2) {
+                        Thread.currentThread().interrupt();
                         logger.error("Discovery.Publisher sleep interrupted");
                     }
                     return;
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/FeatureServerPool.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/FeatureServerPool.java
index dd1c7c32..5f93d2a3 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/FeatureServerPool.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/FeatureServerPool.java
@@ -168,17 +168,25 @@ public class FeatureServerPool
         logger.info("Starting FeatureServerPool");
         Server.startup(CONFIG_FILE);
         TargetLock.startup();
-        droolsTimeoutMillis =
-            getProperty(BUCKET_DROOLS_TIMEOUT, DEFAULT_BUCKET_DROOLS_TIMEOUT);
+        setDroolsTimeoutMillis(
+            getProperty(BUCKET_DROOLS_TIMEOUT, DEFAULT_BUCKET_DROOLS_TIMEOUT));
         int intTimeToLive =
             getProperty(BUCKET_TIME_TO_LIVE, DEFAULT_BUCKET_TIME_TO_LIVE);
-        timeToLiveSecond = String.valueOf(intTimeToLive);
+        setTimeToLiveSecond(String.valueOf(intTimeToLive));
         buildKeywordTable();
         Bucket.Backup.register(new DroolsSessionBackup());
         Bucket.Backup.register(new TargetLock.LockBackup());
         return false;
     }
 
+    private static void setDroolsTimeoutMillis(long timeoutMs) {
+        droolsTimeoutMillis = timeoutMs;
+    }
+
+    private static void setTimeToLiveSecond(String ttlSec) {
+        timeToLiveSecond = ttlSec;
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -319,7 +327,7 @@ public class FeatureServerPool
                 path = Arrays.copyOf(path, path.length);
                 path[path.length - 1] = fieldName;
             }
-            keyword = sco.getString(path);
+            keyword = sco.getString((Object[]) path);
 
             if (keyword != null) {
                 if (conversionFunctionName != null) {
@@ -554,21 +562,11 @@ public class FeatureServerPool
                 continue;
             }
 
-            int beginIndex = begin.length();
-            int endIndex = name.length() - end.length();
-            if (beginIndex < endIndex) {
-                // <topic> is specified, so this table is limited to this
-                // specific topic
-                topic = name.substring(beginIndex, endIndex);
-            }
+            topic = detmTopic(name, begin, end);
 
             // now, process the value
             // Example: requestID,CommonHeader.RequestID
-            String[] commaSeparatedEntries = prop.getProperty(name).split(",");
-            String[][] paths = new String[commaSeparatedEntries.length][];
-            for (int i = 0; i < commaSeparatedEntries.length; i += 1) {
-                paths[i] = commaSeparatedEntries[i].split("\\.");
-            }
+            String[][] paths = splitPaths(prop, name);
 
             if (topic == null) {
                 // these paths are used for any topics not explicitly
@@ -581,6 +579,28 @@ public class FeatureServerPool
         }
     }
 
+    private static String detmTopic(String name, String begin, String end) {
+        int beginIndex = begin.length();
+        int endIndex = name.length() - end.length();
+        if (beginIndex < endIndex) {
+            // <topic> is specified, so this table is limited to this
+            // specific topic
+            return name.substring(beginIndex, endIndex);
+        }
+
+        return null;
+    }
+
+    private static String[][] splitPaths(Properties prop, String name) {
+        String[] commaSeparatedEntries = prop.getProperty(name).split(",");
+        String[][] paths = new String[commaSeparatedEntries.length][];
+        for (int i = 0; i < commaSeparatedEntries.length; i += 1) {
+            paths[i] = commaSeparatedEntries[i].split("\\.");
+        }
+
+        return paths;
+    }
+
     /*======================================*/
     /* 'DroolsPdpStateControlApi' interface */
     /*======================================*/
@@ -993,8 +1013,10 @@ public class FeatureServerPool
                     }
                 };
                 kieSession.insert(doRestore);
+                ois.close();
                 return sessionLatch;
             } else {
+                ois.close();
                 logger.error("{}: Invalid session data for session={}, type={}",
                              this, session.getFullName(), obj.getClass().getName());
             }
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Keyword.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Keyword.java
index c9f4c782..0059a4b9 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Keyword.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Keyword.java
@@ -26,7 +26,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.function.Function;
+import java.util.function.UnaryOperator;
 import lombok.AllArgsConstructor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -183,33 +183,26 @@ public class Keyword {
      * and all the way up the superclass chain.
      */
     private static Class<?> buildReflectiveLookupFindKeyClass(Class<?> clazz) {
-        Class<?> keyClass = null;
         for (Class<?> cl = clazz; cl != null; cl = cl.getSuperclass()) {
             if (classNameToSequence.containsKey(cl.getName())) {
                 // matches the class
-                keyClass = cl;
-                break;
+                return cl;
             }
             for (Class<?> intf : cl.getInterfaces()) {
                 if (classNameToSequence.containsKey(intf.getName())) {
                     // matches one of the interfaces
-                    keyClass = intf;
-                    break;
+                    return intf;
                 }
                 // interface can have superclass
                 for (Class<?> cla = clazz; cla != null; cla = intf.getSuperclass()) {
                     if (classNameToSequence.containsKey(cla.getName())) {
                         // matches the class
-                        keyClass = cla;
-                        break;
+                        return cla;
                     }
                 }
             }
-            if (keyClass != null) {
-                break;
-            }
         }
-        return keyClass;
+        return null;
     }
 
     private static Lookup buildReflectiveLookupBuild(Class<?> clazz, Class<?> keyClass) {
@@ -438,7 +431,7 @@ public class Keyword {
      */
 
     // used to lookup optional conversion functions
-    private static Map<String, Function<String, String>> conversionFunction =
+    private static Map<String, UnaryOperator<String>> conversionFunction =
         new ConcurrentHashMap<>();
 
     // conversion function 'uuid':
@@ -459,7 +452,7 @@ public class Keyword {
      * @param name the conversion function name
      * @param function the object that does the transformation
      */
-    public static void addConversionFunction(String name, Function<String, String> function) {
+    public static void addConversionFunction(String name, UnaryOperator<String> function) {
         conversionFunction.put(name, function);
     }
 
@@ -478,7 +471,7 @@ public class Keyword {
         }
 
         // look up the function
-        Function<String, String> function = conversionFunction.get(functionName);
+        UnaryOperator<String> function = conversionFunction.get(functionName);
         if (function == null) {
             logger.error("{}: conversion function not found", functionName);
             return null;
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Leader.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Leader.java
index 96b6598b..1a596455 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Leader.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Leader.java
@@ -41,6 +41,7 @@ import java.util.UUID;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.core.MediaType;
 import lombok.EqualsAndHashCode;
+import lombok.Setter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -64,9 +65,11 @@ class Leader {
     }
 
     // Server currently in the leader roll
+    @Setter
     private static Server leaderLocal = null;
 
     // Vote state machine -- it is null, unless a vote is in progress
+    @Setter
     private static VoteCycle voteCycle = null;
 
     private static UUID emptyUUID = new UUID(0L, 0L);
@@ -172,7 +175,7 @@ class Leader {
             if (server == leaderLocal) {
                 // the lead server has failed --
                 // start/restart the VoteCycle state machine
-                leaderLocal = null;
+                setLeaderLocal(null);
                 startVoting();
 
                 // send out a notification that the lead server has failed
@@ -296,7 +299,7 @@ class Leader {
             // 5 second grace period has passed -- the leader is one with
             // the most votes, which is the first entry in 'voteData'
             Server oldLeader = leaderLocal;
-            leaderLocal = Server.getServer(voteData.first().uuid);
+            setLeaderLocal(Server.getServer(voteData.first().uuid));
             if (leaderLocal != oldLeader) {
                 // the leader has changed -- send out notifications
                 for (Events listener : Events.getListeners()) {
@@ -319,7 +322,7 @@ class Leader {
 
             // we are done with voting -- clean up, and report results
             MainLoop.removeBackgroundWork(this);
-            voteCycle = null;
+            setVoteCycle(null);
 
             ByteArrayOutputStream bos = new ByteArrayOutputStream();
             PrintStream out = new PrintStream(bos);
@@ -332,6 +335,11 @@ class Leader {
             out.format(format, "UUID", "Votes", "Voter(s)");
             out.format(format, "----", "-----", "--------");
 
+            outputVotes(out, format);
+            logger.info("Output - {}", bos);
+        }
+
+        private void outputVotes(PrintStream out, String format) {
             for (VoteData vote : voteData) {
                 if (vote.voters.isEmpty()) {
                     out.format(format, vote.uuid, 0, "");
@@ -348,7 +356,6 @@ class Leader {
                     }
                 }
             }
-            logger.info("Output - {}", bos);
         }
 
         /**
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Server.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Server.java
index d310805a..80b5891a 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Server.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/Server.java
@@ -81,6 +81,7 @@ import javax.ws.rs.client.Entity;
 import javax.ws.rs.client.WebTarget;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
+import lombok.Setter;
 import org.glassfish.jersey.client.ClientProperties;
 import org.onap.policy.common.endpoints.event.comm.bus.internal.BusTopicParams;
 import org.onap.policy.common.endpoints.http.client.HttpClient;
@@ -105,6 +106,7 @@ public class Server implements Comparable<Server> {
         new TreeMap<>(Util.uuidComparator);
 
     // subset of servers to be notified (null means it needs to be rebuilt)
+    @Setter
     private static LinkedList<Server> notifyList = null;
 
     // data to be sent out to notify list
@@ -320,7 +322,6 @@ public class Server implements Comparable<Server> {
             InetAddress address = InetAddress.getByName(ipAddressString);
             InetSocketAddress socketAddress = new InetSocketAddress(address, port);
 
-            possibleError = "HTTP server initialization error";
             restServer = HttpServletServerFactoryInstance.getServerFactory().build(
                          "SERVER-POOL",                                 // name
                          useHttps,                                      // https
@@ -342,7 +343,6 @@ public class Server implements Comparable<Server> {
             }
 
             // we may not know the port until after the server is started
-            possibleError = "HTTP server start error";
             restServer.start();
             possibleError = null;
 
@@ -625,7 +625,7 @@ public class Server implements Comparable<Server> {
         updatedList.add(this);
 
         // notify list will need to be rebuilt
-        notifyList = null;
+        setNotifyList(null);
 
         if (socketAddress != null && this != thisServer) {
             // initialize 'client' and 'target' fields
@@ -769,60 +769,63 @@ public class Server implements Comparable<Server> {
         // The 'notifyList' value is initially 'null', and it is reset to 'null'
         // every time a new host joins, or one leaves. That way, it is marked for
         // recalculation, but only when needed.
-        if (notifyList == null) {
-            // next index we are looking for
-            int dest = 1;
-
-            // our current position in the Server table -- starting at 'thisServer'
-            UUID current = thisServer.uuid;
-
-            // site socket address of 'current'
-            InetSocketAddress thisSiteSocketAddress = thisServer.siteSocketAddress;
-
-            // hash set of all site socket addresses located
-            HashSet<InetSocketAddress> siteSocketAddresses = new HashSet<>();
-            siteSocketAddresses.add(thisSiteSocketAddress);
-
-            // the list we are building
-            notifyList = new LinkedList<>();
-
-            int index = 1;
-            for ( ; ; ) {
-                // move to the next key (UUID) -- if we hit the end of the table,
-                // wrap to the beginning
-                current = servers.higherKey(current);
-                if (current == null) {
-                    current = servers.firstKey();
-                }
-                if (current.equals(thisServer.uuid)) {
-                    // we have looped through the entire list
-                    break;
-                }
+        if (notifyList != null) {
+            return notifyList;
+        }
 
-                // fetch associated server & site socket address
-                Server server = servers.get(current);
-                InetSocketAddress currentSiteSocketAddress =
-                    server.siteSocketAddress;
-
-                if (Objects.equals(thisSiteSocketAddress,
-                                   currentSiteSocketAddress)) {
-                    // same site -- see if we should add this one
-                    if (index == dest) {
-                        // this is the next index we are looking for --
-                        // add the server
-                        notifyList.add(server);
-
-                        // advance to the next offset (current-offset * 2)
-                        dest = dest << 1;
-                    }
-                    index += 1;
-                } else if (!siteSocketAddresses.contains(currentSiteSocketAddress)) {
-                    // we need at least one member from each site
+        // next index we are looking for
+        int dest = 1;
+
+        // our current position in the Server table -- starting at 'thisServer'
+        UUID current = thisServer.uuid;
+
+        // site socket address of 'current'
+        InetSocketAddress thisSiteSocketAddress = thisServer.siteSocketAddress;
+
+        // hash set of all site socket addresses located
+        HashSet<InetSocketAddress> siteSocketAddresses = new HashSet<>();
+        siteSocketAddresses.add(thisSiteSocketAddress);
+
+        // the list we are building
+        notifyList = new LinkedList<>();
+
+        int index = 1;
+        for ( ; ; ) {
+            // move to the next key (UUID) -- if we hit the end of the table,
+            // wrap to the beginning
+            current = servers.higherKey(current);
+            if (current == null) {
+                current = servers.firstKey();
+            }
+            if (current.equals(thisServer.uuid)) {
+                // we have looped through the entire list
+                break;
+            }
+
+            // fetch associated server & site socket address
+            Server server = servers.get(current);
+            InetSocketAddress currentSiteSocketAddress =
+                server.siteSocketAddress;
+
+            if (Objects.equals(thisSiteSocketAddress,
+                               currentSiteSocketAddress)) {
+                // same site -- see if we should add this one
+                if (index == dest) {
+                    // this is the next index we are looking for --
+                    // add the server
                     notifyList.add(server);
-                    siteSocketAddresses.add(currentSiteSocketAddress);
+
+                    // advance to the next offset (current-offset * 2)
+                    dest = dest << 1;
                 }
+                index += 1;
+            } else if (!siteSocketAddresses.contains(currentSiteSocketAddress)) {
+                // we need at least one member from each site
+                notifyList.add(server);
+                siteSocketAddresses.add(currentSiteSocketAddress);
             }
         }
+
         return notifyList;
     }
 
@@ -932,27 +935,8 @@ public class Server implements Comparable<Server> {
              * This method is running within the 'MainLoop' thread.
              */
             try {
-                WebTarget webTarget = target.path(path);
-                if (responseCallback != null) {
-                    // give callback a chance to modify 'WebTarget'
-                    webTarget = responseCallback.webTarget(webTarget);
+                invokeWebTarget(path, entity, responseCallback);
 
-                    // send the response to the callback
-                    Response response;
-                    if (entity == null) {
-                        response = webTarget.request().get();
-                    } else {
-                        response = webTarget.request().post(entity);
-                    }
-                    responseCallback.response(response);
-                } else {
-                    // just do the invoke, and ignore the response
-                    if (entity == null) {
-                        webTarget.request().get();
-                    } else {
-                        webTarget.request().post(entity);
-                    }
-                }
             } catch (Exception e) {
                 logger.error("Failed to send to {} ({}, {})",
                              uuid, destSocketAddress, destName);
@@ -968,6 +952,30 @@ public class Server implements Comparable<Server> {
         });
     }
 
+    private void invokeWebTarget(final String path, final Entity<?> entity, PostResponse responseCallback) {
+        WebTarget webTarget = target.path(path);
+        if (responseCallback != null) {
+            // give callback a chance to modify 'WebTarget'
+            webTarget = responseCallback.webTarget(webTarget);
+
+            // send the response to the callback
+            Response response;
+            if (entity == null) {
+                response = webTarget.request().get();
+            } else {
+                response = webTarget.request().post(entity);
+            }
+            responseCallback.response(response);
+        } else {
+            // just do the invoke, and ignore the response
+            if (entity == null) {
+                webTarget.request().get();
+            } else {
+                webTarget.request().post(entity);
+            }
+        }
+    }
+
     /**
      * This method may be invoked from any thread.
      *
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/TargetLock.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/TargetLock.java
index 1637e9ef..470801e2 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/TargetLock.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/TargetLock.java
@@ -83,6 +83,8 @@ import org.slf4j.LoggerFactory;
  *     owned by the host containing the entry.
  */
 public class TargetLock implements Lock, Serializable {
+    private static final String LOCK_MSG = "(key={},owner={},uuid={},ttl={})";
+
     private static final long serialVersionUID = 1L;
 
     private static Logger logger = LoggerFactory.getLogger(TargetLock.class);
@@ -550,7 +552,7 @@ public class TargetLock implements Lock, Serializable {
                     WebTarget webTarget = server.getWebTarget("lock/free");
                     if (webTarget != null) {
                         logger.warn("Forwarding 'lock/free' to uuid {} "
-                                    + "(key={},owner={},uuid={},ttl={})",
+                                    + LOCK_MSG,
                                     server.getUuid(), key, ownerKey, uuid, ttl);
                         return webTarget
                                .queryParam(QP_KEY, key)
@@ -565,7 +567,7 @@ public class TargetLock implements Lock, Serializable {
             // if we reach this point, we didn't forward for some reason --
             // return failure by indicating it is locked and unavailable
             logger.error("Couldn't forward 'lock/free' "
-                         + "(key={},owner={},uuid={},ttl={})",
+                         + LOCK_MSG,
                          key, ownerKey, uuid, ttl);
             return null;
         }
@@ -599,7 +601,7 @@ public class TargetLock implements Lock, Serializable {
                     WebTarget webTarget = server.getWebTarget("lock/locked");
                     if (webTarget != null) {
                         logger.warn("Forwarding 'lock/locked' to uuid {} "
-                                    + "(key={},owner={},uuid={},ttl={})",
+                                    + LOCK_MSG,
                                     server.getUuid(), key, ownerKey, uuid, ttl);
                         return webTarget
                                .queryParam(QP_KEY, key)
@@ -614,42 +616,15 @@ public class TargetLock implements Lock, Serializable {
             // if we reach this point, we didn't forward for some reason --
             // return failure by indicating it is locked and unavailable
             logger.error("Couldn't forward 'lock/locked' "
-                         + "(key={},owner={},uuid={},ttl={})",
+                         + LOCK_MSG,
                          key, ownerKey, uuid, ttl);
             return Response.noContent().status(LOCKED).build();
         }
 
-        TargetLock targetLock = null;
+        TargetLock targetLock;
         LocalLocks localLocks = LocalLocks.get(ownerKey);
         synchronized (localLocks) {
-            WeakReference<TargetLock> wr =
-                localLocks.uuidToWeakReference.get(uuid);
-
-            if (wr != null) {
-                targetLock = wr.get();
-                if (targetLock == null) {
-                    // lock has been abandoned
-                    // (AbandonedHandler should usually find this first)
-                    localLocks.weakReferenceToIdentity.remove(wr);
-                    localLocks.uuidToWeakReference.remove(uuid);
-                } else {
-                    // the lock has been made available -- update the state
-                    // TBD: This could be outside of 'synchronized (localLocks)'
-                    synchronized (targetLock) {
-                        if (targetLock.state == State.WAITING) {
-                            targetLock.state = State.ACTIVE;
-                        } else {
-                            // will return a failure -- not sure how this happened
-                            logger.error("incomingLocked: {} is in state {}",
-                                         targetLock, targetLock.state);
-                            targetLock = null;
-                        }
-                    }
-                }
-            } else {
-                // clean up what we can
-                localLocks.uuidToWeakReference.remove(uuid);
-            }
+            targetLock = grabLock(uuid, localLocks);
         }
         if (targetLock == null) {
             // We can't locate the target lock
@@ -661,6 +636,39 @@ public class TargetLock implements Lock, Serializable {
         }
     }
 
+    private static TargetLock grabLock(UUID uuid, LocalLocks localLocks) {
+        WeakReference<TargetLock> wr =
+            localLocks.uuidToWeakReference.get(uuid);
+
+        if (wr != null) {
+            TargetLock targetLock = wr.get();
+            if (targetLock == null) {
+                // lock has been abandoned
+                // (AbandonedHandler should usually find this first)
+                localLocks.weakReferenceToIdentity.remove(wr);
+                localLocks.uuidToWeakReference.remove(uuid);
+            } else {
+                // the lock has been made available -- update the state
+                // TBD: This could be outside of 'synchronized (localLocks)'
+                synchronized (targetLock) {
+                    if (targetLock.state == State.WAITING) {
+                        targetLock.state = State.ACTIVE;
+                        return targetLock;
+                    } else {
+                        // will return a failure -- not sure how this happened
+                        logger.error("incomingLocked: {} is in state {}",
+                                     targetLock, targetLock.state);
+                    }
+                }
+            }
+        } else {
+            // clean up what we can
+            localLocks.uuidToWeakReference.remove(uuid);
+        }
+
+        return null;
+    }
+
     /**
      * This is called when the state of a bucket has changed, but is currently
      * stable. Note that this method is called while being synchronized on the
@@ -1778,6 +1786,12 @@ public class TargetLock implements Lock, Serializable {
                 }
             }
 
+            dumpMergeData(out);
+            dumpServerTable(out);
+            dumpClientOnlyEntries(out);
+        }
+
+        private void dumpMergeData(PrintStream out) {
             if (detail) {
                 // generate format based upon the maximum key length, maximum
                 // owner key length, and whether comments are included anywhere
@@ -1801,9 +1815,6 @@ public class TargetLock implements Lock, Serializable {
                 out.printf(format, "Key", "Owner Key", "UUID", "State", "Comments");
                 out.printf(format, "---", PRINTOUT_DASHES, "----", "-----", "--------");
             }
-
-            dumpServerTable(out);
-            dumpClientOnlyEntries(out);
         }
 
         private void dumpServerTable(PrintStream out) {
@@ -2060,23 +2071,7 @@ public class TargetLock implements Lock, Serializable {
                         clientDataList.add(clientData);
 
                         synchronized (localLocks) {
-                            for (WeakReference<TargetLock> wr :
-                                    localLocks.weakReferenceToIdentity.keySet()) {
-                                // Note: 'targetLock' may be 'null' if it has
-                                // been abandoned, and garbage collected
-                                TargetLock targetLock = wr.get();
-
-                                // fetch associated 'identity'
-                                Identity identity =
-                                    localLocks.weakReferenceToIdentity.get(wr);
-                                if (identity != null) {
-                                    // add a new 'ClientDataRecord' for this bucket
-                                    clientData.clientDataRecords.add(
-                                        new ClientDataRecord(identity,
-                                            (targetLock == null ? null :
-                                            targetLock.getState())));
-                                }
-                            }
+                            generateClientLockData(localLocks, clientData);
                         }
                     }
 
@@ -2089,6 +2084,26 @@ public class TargetLock implements Lock, Serializable {
                     }
                 }
             }
+
+            private void generateClientLockData(LocalLocks localLocks, ClientData clientData) {
+                for (WeakReference<TargetLock> wr :
+                        localLocks.weakReferenceToIdentity.keySet()) {
+                    // Note: 'targetLock' may be 'null' if it has
+                    // been abandoned, and garbage collected
+                    TargetLock targetLock = wr.get();
+
+                    // fetch associated 'identity'
+                    Identity identity =
+                        localLocks.weakReferenceToIdentity.get(wr);
+                    if (identity != null) {
+                        // add a new 'ClientDataRecord' for this bucket
+                        clientData.clientDataRecords.add(
+                            new ClientDataRecord(identity,
+                                (targetLock == null ? null :
+                                targetLock.getState())));
+                    }
+                }
+            }
         }
 
         /**
@@ -2223,28 +2238,8 @@ public class TargetLock implements Lock, Serializable {
                 if (globalLocks != null) {
                     Map<String, LockEntry> keyToEntry = globalLocks.keyToEntry;
                     synchronized (keyToEntry) {
-                        LockEntry le = keyToEntry.get(identity.key);
-                        if (le != null) {
-                            if (identity.uuid.equals(le.currentOwnerUuid)
-                                    && identity.ownerKey.equals(le.currentOwnerKey)) {
-                                // we found a match
-                                continue;
-                            }
-
-                            // check the waiting list
-                            boolean match = false;
-                            for (Waiting waiting : le.waitingList) {
-                                if (identity.uuid.equals(waiting.ownerUuid)
-                                        && identity.ownerKey.equals(waiting.ownerKey)) {
-                                    // we found a match on the waiting list
-                                    match = true;
-                                    break;
-                                }
-                            }
-                            if (match) {
-                                // there was a match on the waiting list
-                                continue;
-                            }
+                        if (matchIdentity(keyToEntry, identity)) {
+                            continue;
                         }
                     }
                 }
@@ -2265,6 +2260,28 @@ public class TargetLock implements Lock, Serializable {
             }
         }
 
+        private boolean matchIdentity(Map<String, LockEntry> keyToEntry, Identity identity) {
+            LockEntry le = keyToEntry.get(identity.key);
+            if (le != null) {
+                if (identity.uuid.equals(le.currentOwnerUuid)
+                        && identity.ownerKey.equals(le.currentOwnerKey)) {
+                    // we found a match
+                    return true;
+                }
+
+                // check the waiting list
+                for (Waiting waiting : le.waitingList) {
+                    if (identity.uuid.equals(waiting.ownerUuid)
+                            && identity.ownerKey.equals(waiting.ownerKey)) {
+                        // we found a match on the waiting list
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
         private void generateResponseServerEnd(AuditData response, boolean includeWarnings) {
             for (Identity identity : serverData) {
                 // remote end is the server, and we are the client
@@ -2779,7 +2796,7 @@ public class TargetLock implements Lock, Serializable {
 
             // send new list to other end
             response = server
-                       .getWebTarget("lock/audit")
+                       .getWebTarget(LOCK_AUDIT)
                        .queryParam(QP_SERVER, server.getUuid().toString())
                        .queryParam(QP_TTL, timeToLive)
                        .request().post(entity);
diff --git a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/persistence/Persistence.java b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/persistence/Persistence.java
index 48bd1c1a..e8121f3a 100644
--- a/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/persistence/Persistence.java
+++ b/feature-server-pool/src/main/java/org/onap/policy/drools/serverpool/persistence/Persistence.java
@@ -245,6 +245,11 @@ public class Persistence implements PolicySessionFeatureApi, ServerPoolApi {
             servers.add(bucket.getPrimaryBackup());
             servers.add(bucket.getSecondaryBackup());
         }
+        sendLocksToBackupServers(bucketNumber, entity, count, servers);
+    }
+
+    private static void sendLocksToBackupServers(final int bucketNumber, final Entity<String> entity, final int count,
+                    Set<Server> servers) {
         for (final Server server : servers) {
             if (server != null) {
                 // send out REST command
@@ -336,25 +341,7 @@ public class Persistence implements PolicySessionFeatureApi, ServerPoolApi {
                             servers.add(bucket.getPrimaryBackup());
                             servers.add(bucket.getSecondaryBackup());
                         }
-                        for (final Server server : servers) {
-                            if (server != null) {
-                                // send out REST command
-                                server.getThreadPool().execute(() -> {
-                                    WebTarget webTarget =
-                                        server.getWebTarget("persistence/session");
-                                    if (webTarget != null) {
-                                        webTarget
-                                        .queryParam(QP_BUCKET,
-                                                    bucket.getIndex())
-                                        .queryParam(QP_SESSION,
-                                                    encodedSessionName)
-                                        .queryParam(QP_COUNT, count)
-                                        .queryParam(QP_DEST, server.getUuid())
-                                        .request().post(entity);
-                                    }
-                                });
-                            }
-                        }
+                        sendBucketToBackupServers(bucket, count, entity, servers);
                     }
                 }
             } catch (Exception e) {
@@ -362,6 +349,30 @@ public class Persistence implements PolicySessionFeatureApi, ServerPoolApi {
             }
         }
 
+        private void sendBucketToBackupServers(Bucket bucket, final int count, final Entity<String> entity,
+                        Set<Server> servers) {
+
+            for (final Server server : servers) {
+                if (server != null) {
+                    // send out REST command
+                    server.getThreadPool().execute(() -> {
+                        WebTarget webTarget =
+                            server.getWebTarget("persistence/session");
+                        if (webTarget != null) {
+                            webTarget
+                            .queryParam(QP_BUCKET,
+                                        bucket.getIndex())
+                            .queryParam(QP_SESSION,
+                                        encodedSessionName)
+                            .queryParam(QP_COUNT, count)
+                            .queryParam(QP_DEST, server.getUuid())
+                            .request().post(entity);
+                        }
+                    });
+                }
+            }
+        }
+
         /* ************************************** */
         /* 'RuleRuntimeEventListener' interface   */
         /* ************************************** */
@@ -690,57 +701,20 @@ public class Persistence implements PolicySessionFeatureApi, ServerPoolApi {
                 String sessionName = entry.getKey();
                 ReceiverSessionBucketData rsbd = entry.getValue();
 
-                // [0]="<groupId>" [1]="<artifactId>", [2]="<sessionName>"
-                String[] nameSegments = sessionName.split(":");
-                PolicySession policySession = null;
-
-                // locate the 'PolicyContainer' and 'PolicySession'
-                if (nameSegments.length == 3) {
-                    // step through all 'PolicyContainer' instances looking
-                    // for a matching 'artifactId' & 'groupId'
-                    for (PolicyContainer pc : PolicyContainer.getPolicyContainers()) {
-                        if (nameSegments[1].equals(pc.getArtifactId())
-                                && nameSegments[0].equals(pc.getGroupId())) {
-                            // 'PolicyContainer' matches -- try to fetch the session
-                            policySession = pc.getPolicySession(nameSegments[2]);
-                            break;
-                        }
-                    }
-                }
-
+                PolicySession policySession = detmPolicySession(sessionName);
                 if (policySession == null) {
                     logger.error(RESTORE_BUCKET_ERROR
                                  + "Can't find PolicySession{}", sessionName);
                     continue;
                 }
 
-                Object obj = null;
-                try {
-                    // deserialization needs to use the correct 'ClassLoader'
-                    obj = Util.deserialize(Base64.getDecoder().decode(rsbd.encodedSerializedData),
-                        policySession.getPolicyContainer().getClassLoader());
-                } catch (IOException | ClassNotFoundException | IllegalArgumentException e) {
-                    logger.error(RESTORE_BUCKET_ERROR
-                                 + "Failed to read data for session '{}'",
-                                 sessionName, e);
-
-                    // can't decode -- skip this session
-                    continue;
-                }
-
-                if (!(obj instanceof Map)) {
-                    logger.error(RESTORE_BUCKET_ERROR
-                                 + "Session '{}' data has class {}, expected 'Map'",
-                                 sessionName, obj.getClass().getName());
-
-                    // wrong object type decoded -- skip this session
+                final Map<?, ?> droolsObjects = deserializeMap(sessionName, rsbd, policySession);
+                if (droolsObjects == null) {
                     continue;
                 }
 
                 // if we reach this point, we have decoded the persistent data
 
-                final Map<?, ?> droolsObjects = (Map<?, ?>) obj;
-
                 // signal when restore is complete
                 final CountDownLatch sessionLatch = new CountDownLatch(1);
 
@@ -767,6 +741,56 @@ public class Persistence implements PolicySessionFeatureApi, ServerPoolApi {
             return sessionLatches;
         }
 
+        private PolicySession detmPolicySession(String sessionName) {
+            // [0]="<groupId>" [1]="<artifactId>", [2]="<sessionName>"
+            String[] nameSegments = sessionName.split(":");
+
+            // locate the 'PolicyContainer' and 'PolicySession'
+            if (nameSegments.length == 3) {
+                // step through all 'PolicyContainer' instances looking
+                // for a matching 'artifactId' & 'groupId'
+                for (PolicyContainer pc : PolicyContainer.getPolicyContainers()) {
+                    if (nameSegments[1].equals(pc.getArtifactId())
+                            && nameSegments[0].equals(pc.getGroupId())) {
+                        // 'PolicyContainer' matches -- try to fetch the session
+                        return pc.getPolicySession(nameSegments[2]);
+                    }
+                }
+            }
+            return null;
+        }
+
+        private Map<?, ?> deserializeMap(String sessionName, ReceiverSessionBucketData rsbd,
+                        PolicySession policySession) {
+            Object obj;
+
+            try {
+                // deserialization needs to use the correct 'ClassLoader'
+                obj = Util.deserialize(Base64.getDecoder().decode(rsbd.encodedSerializedData),
+                    policySession.getPolicyContainer().getClassLoader());
+            } catch (IOException | ClassNotFoundException | IllegalArgumentException e) {
+                logger.error(RESTORE_BUCKET_ERROR
+                             + "Failed to read data for session '{}'",
+                             sessionName, e);
+
+                // can't decode -- skip this session
+                return null;
+            }
+
+            if (!(obj instanceof Map)) {
+                logger.error(RESTORE_BUCKET_ERROR
+                             + "Session '{}' data has class {}, expected 'Map'",
+                             sessionName, obj.getClass().getName());
+
+                // wrong object type decoded -- skip this session
+                return null;
+            }
+
+            // if we reach this point, we have decoded the persistent data
+
+            return (Map<?, ?>) obj;
+        }
+
         private void restoreBucketLocks(Bucket bucket) {
             if (lockData != null) {
                 Object obj = null;