=== modified file 'CHANGES'
--- CHANGES	2009-12-18 22:39:31 +0000
+++ CHANGES	2010-01-12 20:34:03 +0000
@@ -3,6 +3,9 @@
 
 mm-dd-yy - Version 5.1.11 (not yet released)
  
+    - Fix for BUG#50288 - NullPointerException possible during invalidateCurrentConnection() for load-balanced
+      connections.
+ 
     - Fix for BUG#49745 - deleteRow() for updatable result sets can cause full table scan because escaped hex 
       values are used for primary key identifiers.
  

=== modified file 'src/com/mysql/jdbc/LoadBalancingConnectionProxy.java'
--- src/com/mysql/jdbc/LoadBalancingConnectionProxy.java	2009-11-19 15:30:38 +0000
+++ src/com/mysql/jdbc/LoadBalancingConnectionProxy.java	2010-01-12 20:32:00 +0000
@@ -285,19 +285,15 @@
 			// remove from liveConnections
 			this.liveConnections.remove(this.connectionsToHostsMap
 					.get(this.currentConn));
-			if(this.connectionsToHostsMap.containsKey(this.currentConn)){
-				int hostIndex = ((Integer) this.hostsToListIndexMap
-						.get(this.connectionsToHostsMap.get(this.currentConn)))
-						.intValue();
-	
+			Object mappedHost = this.connectionsToHostsMap.remove(this.currentConn);
+			if(mappedHost != null && this.hostsToListIndexMap.containsKey(mappedHost)){
+				int hostIndex = ((Integer) this.hostsToListIndexMap.get(mappedHost)).intValue();
 				// reset the statistics for the host
 				synchronized (this.responseTimes) {
 					this.responseTimes[hostIndex] = 0;
 				}
 			}
-
-			this.connectionsToHostsMap.remove(this.currentConn);
-			}
+		}
 	}
 	
 	private void closeAllConnections(){