Added comment to explain why NPEs can end up in the log during shutdo…

…wn if there async requests are queued up.
maksred · Oct 11, 2012 · 79d9163 · 79d9163
1 parent a34e62a
commit 79d9163
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/src/java/voldemort/store/socket/clientrequest/ClientRequestExecutorPool.java b/src/java/voldemort/store/socket/clientrequest/ClientRequestExecutorPool.java
@@ -317,6 +317,11 @@ public void handleException(Exception e) {
                 e = new UnreachableStoreException("Failure in " + operationName + ": "
                                                   + e.getMessage(), e);
             try {
+                // Because PerformParallel(Put||Delete|GetAll)Requests define
+                // 'callback' via an anonymous class, callback can be null if
+                // the client factory closes down and some other thread invokes
+                // this code. This can cause NullPointerExceptions during
+                // shutdown if async resource requests are queued up.
                 callback.requestComplete(e, 0);
             } catch(Exception ex) {
                 if(logger.isEnabledFor(Level.WARN))