Minor changes addressing Pavlin's concerns
diff --git a/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java b/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
index bb92cf9..b3d9759 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
@@ -297,10 +297,13 @@
 					// send a packet out now
 					FlowPath flow = datagrid.getFlow(new FlowId(existingFlow.flowId));
 					FlowEntry flowEntryForThisSwitch = null;
-					for (FlowEntry flowEntry : flow.flowEntries()) {
-						if (flowEntry.dpid().equals(new Dpid(sw.getId()))) {
-							flowEntryForThisSwitch = flowEntry;
-							break;
+					
+					if (flow != null) {
+						for (FlowEntry flowEntry : flow.flowEntries()) {
+							if (flowEntry.dpid().equals(new Dpid(sw.getId()))) {
+								flowEntryForThisSwitch = flowEntry;
+								break;
+							}
 						}
 					}
 					
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/CallerId.java b/src/main/java/net/onrc/onos/ofcontroller/util/CallerId.java
index ec18f09..a0217d4 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/CallerId.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/CallerId.java
@@ -18,6 +18,7 @@
      * @param otherCallerId
      */
     public CallerId(CallerId otherCallerId) {
+    // Note: make a full copy if we change value to a mutable type
     value = otherCallerId.value;
     }