title: Store thrown exception for CONCURRENT_MAP_REMOVE while using Hazelcast (Java)
body: <p>I am using hazelcast -2.5 in a cluster.  I am trying to load an ArrayList of User defined objects (with a few String fields and one Integer) in the store-load implementation of my Hazelcast Map (String, ArrayList).  The initial load all does not give me any exceptions.  However, if the load gets invoked due to a get call on the map for a key for which there is no value in the map (and hence the load gets called), I see the following exception being thrown (I am also doing a remove operation on the map after that point in time):</p>
  
  <pre><code>Store thrown exception for CONCURRENT_MAP_REMOVE
  </code></pre>
  
  <p>It gives me a class cast exception stating that my UD Object cannot be cast to a String.  I would not be surprised if I missed something in my implementation - its just that when this call is made, I am trying to do a get operation on the map and assigning the result to an ArrayList of User Defined Object.  The load operation in the store-load also returns an ArrayList of User defined object (the store-load is declared in the same way).</p>
  
  <pre><code>WARNING: [192.168.1.1]:5703 [dev] Store thrown exception for CONCURRENT_MAP_REMOVE
  java.lang.ClassCastException: models.test.TestClass cannot be cast to java.lang.String
      at models.test.StoreLoadTestMap.load(StoreLoadTestMap.java:1)
      at com.hazelcast.impl.concurrentmap.MapStoreWrapper.load(MapStoreWrapper.java:143)
      at com.hazelcast.impl.ConcurrentMapManager$RemoveOperationHandler$RemoveLoader.doMapStoreOperation(ConcurrentMapManager.java:2681)
      at com.hazelcast.impl.ConcurrentMapManager$AbstractMapStoreOperation.run(ConcurrentMapManager.java:3860)
      at com.hazelcast.impl.executor.ParallelExecutorService$ParallelExecutorImpl$ExecutionSegment.run(ParallelExecutorService.java:212)
      at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
      at java.lang.Thread.run(Thread.java:662)
      at com.hazelcast.impl.ExecutorThreadFactory$1.run(ExecutorThreadFactory.java:38) 
  </code></pre>
  
  <p>Any ideas on troubleshooting this?  </p>