Close the channel in the finalize() function of OFSwitchImpl.

src/main/java/net/floodlightcontroller/core/internal/Controller.java

@@ -898,7 +898,7 @@ public class Controller
             }
             // will eventually trigger a removeSwitch(), which will cause
             // a "Not removing Switch ... already removed debug message.
-            oldSw.getChannel().close();
+            // oldSw.getChannel().close();
         }
         
         updateActiveSwitchInfo(sw);

src/main/java/net/floodlightcontroller/core/internal/OFSwitchImpl.java

@@ -360,4 +360,9 @@ public class OFSwitchImpl implements IOFSwitch {
 	public TimedCache<Long> getTimedCache() {
         return timedCache;
 	}
+
+    protected void finalize() {
+        if (this.channel != null)
+            this.channel.close();
+    }
 }