Android bug in API 2.4.0?

Comments

• sonalideo

  January 2016

  Exists in 2.3.0 also so likely not new.
• Eric

  January 2016

  1. What are the steps that lead this error?
  2. Can you consistently reproduce said error?
  3. What is the data route you are using?
• sonalideo

  January 2016

  It was a accelerometer data route for boot logging and streaming from a split. It was reproducible and was triggered when doing multiple board resets after each other.

  Now I also see that I get this exception by calling removeRoutes on a board where the setup has failed and no routes have been added. (removeRoutes in DefaultMetawearBoard.java:3809)
• sonalideo

  January 2016 edited January 2016

  Another one on Android 5.1.1. Hard to know what causes it to occur though. Only happens sometimes. But now 3 different ways it crashes on ProcessedDataSignal.unsubscribe. This was in a setup with multiple boards connected at once. Possible race conditions?

  
  

  java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference at

  java.util.concurrent.ConcurrentHashMap.replaceNode(ConcurrentHashMap.java:916)

  at java.util.concurrent.ConcurrentHashMap.remove(ConcurrentHashMap.java:907)

  at com.mbientlab.metawear.impl.DefaultMetaWearBoard$RouteBuilder$ProcessedDataSignal.unsubscribe(DefaultMetaWearBoard.java:1902)

  at com.mbientlab.metawear.impl.DefaultMetaWearBoard$RouteManagerImpl.remove(DefaultMetaWearBoard.java:336)

  at com.mbientlab.metawear.impl.DefaultMetaWearBoard$RouteBuilder$37.run(DefaultMetaWearBoard.java:2793)

  at android.os.Handler.handleCallback(Handler.java:739)

  at android.os.Handler.dispatchMessage(Handler.java:95)

  at android.os.Looper.loop(Looper.java:135)

  at android.app.ActivityThread.main(ActivityThread.java:5254)

  at java.lang.reflect.Method.invoke(Native Method)

  at java.lang.reflect.Method.invoke(Method.java:372)

  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)

  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)

  
  
• Eric

  January 2016

  You earlier mentioned that you were only streaming / logging so it's odd that you are running into errors in the ProcessedDataSignal class.  What is the data route you are using (code, not a description) and what are the steps I need to take to (possibly?) trigger the NPE (ordered list of what I need to do)?
• sonalideo

  January 2016

  Code in short:

  
  

  accelModule.routeData().fromAxes().split().branch().log(ACCEL_DATA).branch().process(new Rms()).process(new Comparison(Comparison.Operation.GT, 1)).stream("alarm").end().commit()

  .onComplete(new AsyncOperation.CompletionHandler<RouteManager>() {

  public void failure(Throwable error) {resetBoard();}

  public void success(RouteManager result) {

  result.subscribe("alarm", new RouteManager.MessageHandler() {

  public void process(Message message) {

  loggingModule.downloadLog(0.1f, new Logging.DownloadHandler() {});}});

  result.setLogMessageHandler(ACCEL_DATA, new RouteManager.MessageHandler() {

  public void process(Message message) {}});}});

  
  

  
  

  resetBoard(){

  mwBoard.removeRoutes();

  debugModule.resetDevice();

  }

  
  

  Perhaps possible ways to force a crash:

  * One thread downloading log data

  * One thread resetting board by removing and adding the routes

  * Simultaneously do stream data processing
• sonalideo

  February 2016

  Found one way to make it crash now repeatedly. Add new routes and call disconnect immediately before the routes have been added successfully.
• Eric

  February 2016

  Ok, so you do have data processing in your route.  If there were not any, then that would be a more troubling issue.  I setup null pointer checks for unsubscribing from data processors to address the crash.