#51 adding the required synchronization

Author: shroffk

pvAccessJava/src/org/epics/pvaccess/server/impl/remote/ServerChannelImpl.java

@@ -158,7 +158,7 @@ public Destroyable getRequest(int id) {
 
 	}
 
-	public Destroyable[] getRequests() {
+	public synchronized Destroyable[] getRequests() {
 
 		Destroyable[] reqs = new Destroyable[requests.size()];
 		requests.values().toArray(reqs);

pvAccessJava/src/org/epics/pvaccess/server/impl/remote/tcp/NonBlockingServerTCPTransport.java

@@ -108,12 +108,13 @@ private void destroyAllChannels() {
 
 		context.getLogger().fine("Transport to " + socketAddress + " still has " + channels.size() + " channel(s) active and closing...");
 
-		
-		for(ServerChannel serverChannel : channels.values()) {
-			serverChannel.destroy();
-		}
-		
-		channels.clear();
+        synchronized (channels) {
+            for (ServerChannel serverChannel : channels.values()) {
+                serverChannel.destroy();
+            }
+
+            channels.clear();
+        }
 	}
 
 	/**
@@ -122,13 +123,13 @@ private void destroyAllChannels() {
 	 */
 	public int preallocateChannelSID()
 	{
-		
+		synchronized (channels) {
 			// search first free (theoretically possible loop of death)
 			int sid = lastChannelSID.incrementAndGet();
 			while (channels.containsKey(sid))
 				sid = lastChannelSID.incrementAndGet();
 			return sid;
-		
+		}
 	}
 
 	/**