title: Android app crashes with NullPointerException in ChoreoGrapher
body: <p>I have the following code, trying to create a simple ListAdapter in a ListView (I had this code working before and this is the only place I have changed something):</p>
  
  <pre><code>public BuddyListAdapter(Context context, HashMap&lt;String, Buddy&gt; hashMap) {
      buddyList = new ArrayList&lt;Buddy&gt;(hashMap.values());
      mInflater = LayoutInflater.from(context);
      ctx = context;
  }
  </code></pre>
  
  <p>When stepping through, nothing happens, but when running, I get a <code>NullPointerException</code> in <code>ChoreoGrapher.doCallbacks</code>, when I create an empty <code>ArrayList</code>, it doesn't crash:</p>
  
  <pre><code>public BuddyListAdapter(Context context, HashMap&lt;String, Buddy&gt; hashMap) {
      buddyList = new ArrayList&lt;Buddy&gt;();
      mInflater = LayoutInflater.from(context);
      ctx = context;
  }
  </code></pre>
  
  <p>What is the <code>ChoreoGrapher</code> and why is it crashing my app?</p>
  
  <p>I am completely stuck on what could be the problem, or how to figure out what is wrong. The Eclipse debugger or crash information is not really helping.</p>
  
  <p>The entire stack trace is as follows:</p>
  
  <pre><code>Thread [&lt;1&gt; main] (Suspended (exception NullPointerException))  
      Choreographer.doCallbacks(int, long) line: 558  
      Choreographer.doFrame(long, int) line: 525  
      Choreographer$FrameDisplayEventReceiver.run() line: 711 
      Handler.handleCallback(Message) line: 615   
      Choreographer$FrameHandler(Handler).dispatchMessage(Message) line: 92   
      Looper.loop() line: 137 
      ActivityThread.main(String[]) line: 4745    
      Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]  
      Method.invoke(Object, Object...) line: 511  
      ZygoteInit$MethodAndArgsCaller.run() line: 786  
      ZygoteInit.main(String[]) line: 553 
      NativeStart.main(String[]) line: not available [native method]  
  </code></pre>
  
  <p>I also have a <code>Handler</code> in the main activity. When it is not doing anything, the listview doesn't crash. However, I remove all callbacks from it before openning the listview.</p>