#vulnerable code 
                              @Test
  public void testStateTransitionTimeOut() throws Exception {
    Map<String, SleepStateModelFactory> factories = new HashMap<String, SleepStateModelFactory>();
    IdealState idealState =
        _setupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, TEST_DB);
    for (int i = 0; i < NODE_NR; i++) {
      String instanceName = PARTICIPANT_PREFIX + "_" + (START_PORT + i);
      SleepStateModelFactory factory = new SleepStateModelFactory(1000);
      factories.put(instanceName, factory);
      for (String p : idealState.getPartitionSet()) {
        if (idealState.getPreferenceList(p).get(0).equals(instanceName)) {
          factory.addPartition(p);
        }
      }

      _participants[i] = new MockParticipantManager(ZK_ADDR, CLUSTER_NAME, instanceName);
      _participants[i].getStateMachineEngine().registerStateModelFactory("MasterSlave", factory);
      _participants[i].syncStart();
    }
    String controllerName = CONTROLLER_PREFIX + "_0";
    _controller =
        new ClusterControllerManager(ZK_ADDR, CLUSTER_NAME, controllerName);
    _controller.syncStart();

    boolean result =
        ClusterStateVerifier
            .verifyByZkCallback(new MasterNbInExtViewVerifier(ZK_ADDR, CLUSTER_NAME));
    Assert.assertTrue(result);
    HelixDataAccessor accessor = _participants[0].getHelixDataAccessor();

    Builder kb = accessor.keyBuilder();
    ExternalView ev = accessor.getProperty(kb.externalView(TEST_DB));
    for (String p : idealState.getPartitionSet()) {
      String idealMaster = idealState.getPreferenceList(p).get(0);
      Assert.assertTrue(ev.getStateMap(p).get(idealMaster).equals("ERROR"));

      TimeOutStateModel model = factories.get(idealMaster).getStateModel(TEST_DB, p);
      Assert.assertEquals(model._errorCallcount, 1);
      Assert.assertEquals(model._error.getCode(), ErrorCode.TIMEOUT);
    }
  } 
                            #location 17 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              @Test
  public void testStateTransitionTimeOut() throws Exception {
    _setupTool.addResourceToCluster(CLUSTER_NAME, TEST_DB, _PARTITIONS, STATE_MODEL);
    _setupTool.getClusterManagementTool().enableResource(CLUSTER_NAME, TEST_DB, false);
    _setupTool.rebalanceStorageCluster(CLUSTER_NAME, TEST_DB, 3);

    // Set the timeout values
    StateTransitionTimeoutConfig stateTransitionTimeoutConfig =
        new StateTransitionTimeoutConfig(new ZNRecord(TEST_DB));
    stateTransitionTimeoutConfig.setStateTransitionTimeout("SLAVE", "MASTER", 300);
    ResourceConfig resourceConfig = new ResourceConfig.Builder(TEST_DB)
        .setStateTransitionTimeoutConfig(stateTransitionTimeoutConfig)
        .setRebalanceConfig(new RebalanceConfig(new ZNRecord(TEST_DB)))
        .setNumPartitions(_PARTITIONS).setHelixEnabled(false).build();
    _configAccessor.setResourceConfig(CLUSTER_NAME, TEST_DB, resourceConfig);
    setParticipants(TEST_DB);


    _setupTool.getClusterManagementTool().enableResource(CLUSTER_NAME, TEST_DB, true);
    boolean result =
        ClusterStateVerifier
            .verifyByZkCallback(new MasterNbInExtViewVerifier(ZK_ADDR, CLUSTER_NAME));
    Assert.assertTrue(result);

    verify(TEST_DB);
  }