diff --git a/dspace-api/src/main/java/org/dspace/content/authority/DCInputAuthority.java b/dspace-api/src/main/java/org/dspace/content/authority/DCInputAuthority.java
index 9e350a6414..e2abf0e117 100644
--- a/dspace-api/src/main/java/org/dspace/content/authority/DCInputAuthority.java
+++ b/dspace-api/src/main/java/org/dspace/content/authority/DCInputAuthority.java
@@ -85,6 +85,16 @@ public class DCInputAuthority extends SelfNamedPlugin implements ChoiceAuthority
     }
 
     public static String[] getPluginNames()
+    {
+        if (pluginNames == null)
+        {
+            initPluginNames();
+        }
+        
+        return (String[]) ArrayUtils.clone(pluginNames);
+    }
+
+    private static synchronized void initPluginNames()
     {
         if (pluginNames == null)
         {
@@ -109,7 +119,6 @@ public class DCInputAuthority extends SelfNamedPlugin implements ChoiceAuthority
             pluginNames = names.toArray(new String[names.size()]);
             log.debug("Got plugin names = "+Arrays.deepToString(pluginNames));
         }
-        return (String[]) ArrayUtils.clone(pluginNames);
     }
 
     // once-only load of values and labels
diff --git a/dspace-api/src/main/java/org/dspace/content/authority/DSpaceControlledVocabulary.java b/dspace-api/src/main/java/org/dspace/content/authority/DSpaceControlledVocabulary.java
index 219a784c21..6bb70a9950 100644
--- a/dspace-api/src/main/java/org/dspace/content/authority/DSpaceControlledVocabulary.java
+++ b/dspace-api/src/main/java/org/dspace/content/authority/DSpaceControlledVocabulary.java
@@ -105,6 +105,16 @@ public class DSpaceControlledVocabulary extends SelfNamedPlugin implements Choic
     }
 
     public static String[] getPluginNames()
+    {
+        if (pluginNames == null)
+        {
+            initPluginNames();
+        }
+        
+        return (String[]) ArrayUtils.clone(pluginNames);
+    }
+
+    private static synchronized void initPluginNames()
     {
         if (pluginNames == null)
         {
@@ -125,7 +135,6 @@ public class DSpaceControlledVocabulary extends SelfNamedPlugin implements Choic
         	pluginNames = names.toArray(new String[names.size()]);
             log.info("Got plugin names = "+Arrays.deepToString(pluginNames));
         }
-        return (String[]) ArrayUtils.clone(pluginNames);
     }
 
     private void init()
diff --git a/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java b/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java
index 26cd722850..f6f89090f2 100644
--- a/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java
+++ b/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java
@@ -1020,7 +1020,7 @@ public class OAIHarvester {
 	/**
 	 * Start harvest scheduler.   
 	 */
-	public static void startNewScheduler() throws SQLException, AuthorizeException {
+	public static synchronized void startNewScheduler() throws SQLException, AuthorizeException {
 		Context c = new Context();
 		HarvestedCollection.exists(c);
 		c.complete();
@@ -1037,7 +1037,7 @@ public class OAIHarvester {
 	/**
 	 * Stop an active harvest scheduler.   
 	 */
-	public static void stopScheduler() throws SQLException, AuthorizeException {
+	public static synchronized void stopScheduler() throws SQLException, AuthorizeException {
 		synchronized(HarvestScheduler.lock) {
 			HarvestScheduler.interrupt = HarvestScheduler.HARVESTER_INTERRUPT_STOP;
 			HarvestScheduler.lock.notify();
@@ -1187,34 +1187,35 @@ public class OAIHarvester {
 			{
 				try 
 				{
-					synchronized(interrupt) {
-						switch (interrupt) 
-						{
-						case HARVESTER_INTERRUPT_NONE: 
-							break;
-						case HARVESTER_INTERRUPT_INSERT_THREAD:
-							interrupt = HARVESTER_INTERRUPT_NONE;	
-							addThread(interruptValue);
-							interruptValue = 0;
-							break;
-						case HARVESTER_INTERRUPT_PAUSE:
-							interrupt = HARVESTER_INTERRUPT_NONE;
-							synchronized(status) { 
-								status = HARVESTER_STATUS_PAUSED;
-							}
-							while(interrupt != HARVESTER_INTERRUPT_RESUME && interrupt != HARVESTER_INTERRUPT_STOP) {
-								Thread.sleep(1000);
-							}		
-							if (interrupt != HARVESTER_INTERRUPT_STOP)
-                            {
-                                break;
-                            }
-						case HARVESTER_INTERRUPT_STOP:
-							interrupt = HARVESTER_INTERRUPT_NONE;
-							status = HARVESTER_STATUS_STOPPED;
-							return;
-						}
-					}
+                    synchronized (HarvestScheduler.class) {
+                        switch (interrupt)
+                        {
+                        case HARVESTER_INTERRUPT_NONE:
+                            break;
+                        case HARVESTER_INTERRUPT_INSERT_THREAD:
+                            interrupt = HARVESTER_INTERRUPT_NONE;
+                            addThread(interruptValue);
+                            interruptValue = 0;
+                            break;
+                        case HARVESTER_INTERRUPT_PAUSE:
+                            interrupt = HARVESTER_INTERRUPT_NONE;
+                            status = HARVESTER_STATUS_PAUSED;
+                        case HARVESTER_INTERRUPT_STOP:
+                            interrupt = HARVESTER_INTERRUPT_NONE;
+                            status = HARVESTER_STATUS_STOPPED;
+                            return;
+                        }
+                    }
+
+                    if (status == HARVESTER_STATUS_PAUSED) {
+                        while(interrupt != HARVESTER_INTERRUPT_RESUME && interrupt != HARVESTER_INTERRUPT_STOP) {
+                            Thread.sleep(1000);
+                        }
+                        if (interrupt != HARVESTER_INTERRUPT_STOP)
+                        {
+                            break;
+                        }
+                    }
 
 					status = HARVESTER_STATUS_RUNNING;
 										
@@ -1229,7 +1230,7 @@ public class OAIHarvester {
 					
 					// Stage #2: start up all the threads currently in the queue up to the maximum number 
 					while (!harvestThreads.isEmpty()) {
-						synchronized(activeThreads) {
+						synchronized(HarvestScheduler.class) {
 							activeThreads++;
 						}
 						Thread activeThread = new Thread(harvestThreads.pop());
@@ -1390,7 +1391,7 @@ public class OAIHarvester {
 					context.abort();
 				}
 				
-				synchronized (HarvestScheduler.activeThreads) {
+				synchronized (HarvestScheduler.class) {
 					HarvestScheduler.activeThreads--;
 				}								
 			}