output: #fixed code
                               @SuppressWarnings("unchecked")
  	@Test
  	public void testUpdateOriginProcess() throws ModelException {
  
  		String orignUniqueID = documentContext.getUniqueID();
  
  		/*
  		 * 1.) create test result for new subprcoess.....
  		 */
  		try {
  			documentActivity = this.getModel().getEvent(100, 20);
  			splitAndJoinPlugin.run(documentContext, documentActivity);
  		} catch (PluginException e) {
  			e.printStackTrace();
  			Assert.fail();
  		}
  		Assert.assertNotNull(documentContext);
  
  		// now load the subprocess
  		List<String> workitemRefList = documentContext.getItemValue(SplitAndJoinPlugin.LINK_PROPERTY);
  		String subprocessUniqueid = workitemRefList.get(0);
  		ItemCollection subprocess = this.documentService.load(subprocessUniqueid);
  
  		// test data in subprocess
  		Assert.assertNotNull(subprocess);
  		Assert.assertEquals(100, subprocess.getProcessID());
  
  		/*
  		 * 2.) process the subprocess to test if the origin process will be
  		 * updated correctly
  		 */
  		// add some custom data
  		subprocess.replaceItemValue("_sub_data", "some test data");
  		// now we process the subprocess
  		try {
  			documentActivity = this.getModel().getEvent(100, 50);
  			splitAndJoinPlugin.run(subprocess, documentActivity);
  		} catch (PluginException e) {
  			e.printStackTrace();
  			Assert.fail();
  		}
  		
  		// test orign ref
  		Assert.assertEquals(orignUniqueID,subprocess.getItemValueString(SplitAndJoinPlugin.ORIGIN_REF));
  			
  
  		// load origin document
  		documentContext = documentService.load(orignUniqueID);
  		Assert.assertNotNull(documentContext);
  
  		// test data.... (new $processId=200 and _sub_data from subprocess
  		Assert.assertEquals(100, documentContext.getProcessID());
  		Assert.assertEquals("some test data", documentContext.getItemValueString("_sub_data"));
  
  		
  		
  	}
input: #vulnerable code 
                               @SuppressWarnings("unchecked")
  	@Test
  	public void testUpdateOriginProcess() throws ModelException {
  
  		String orignUniqueID = documentContext.getUniqueID();
  
  		/*
  		 * 1.) create test result for new subprcoess.....
  		 */
  		try {
  			documentActivity = this.getModel().getEvent(100, 20);
  			splitAndJoinPlugin.run(documentContext, documentActivity);
  		} catch (PluginException e) {
  			e.printStackTrace();
  			Assert.fail();
  		}
  		Assert.assertNotNull(documentContext);
  
  		// now load the subprocess
  		List<String> workitemRefList = documentContext.getItemValue(SplitAndJoinPlugin.LINK_PROPERTY);
  		String subprocessUniqueid = workitemRefList.get(0);
  		ItemCollection subprocess = this.documentService.load(subprocessUniqueid);
  
  		// test data in subprocess
  		Assert.assertNotNull(subprocess);
  		Assert.assertEquals(100, subprocess.getProcessID());
  
  		/*
  		 * 2.) process the subprocess to test if the origin process will be
  		 * updated correctly
  		 */
  		// add some custom data
  		subprocess.replaceItemValue("_sub_data", "some test data");
  		// now we process the subprocess
  		try {
  			documentActivity = this.getModel().getEvent(100, 50);
  			splitAndJoinPlugin.run(subprocess, documentActivity);
  		} catch (PluginException e) {
  			e.printStackTrace();
  			Assert.fail();
  		}
  
  		// load origin document
  		documentContext = documentService.load(orignUniqueID);
  		Assert.assertNotNull(documentContext);
  
  		// test data.... (new $processId=200 and _sub_data from subprocess
  		Assert.assertEquals(100, documentContext.getProcessID());
  		Assert.assertEquals("some test data", documentContext.getItemValueString("_sub_data"));
  
  	} 
                              #location 48 
                              #vulnerability type NULL_DEREFERENCE