fix(android): prevent ANRs, delegate them to be handled by system

android/runtime/common/src/java/org/appcelerator/kroll/KrollRuntime.java

@@ -538,7 +538,9 @@ public static void dispatchException(final String title, final String message, f
 			}
 
 			// Handle exception with defaultExceptionHandler
-			instance.primaryExceptionHandler.handleException(exceptionMessage);
+			if (instance.primaryExceptionHandler != null) {
+				instance.primaryExceptionHandler.handleException(exceptionMessage);
+			}
 		}
 	}
 

android/titanium/src/java/org/appcelerator/kroll/KrollProxy.java

@@ -1253,7 +1253,7 @@ public boolean handleMessage(Message msg)
 				}
 			}
 		} catch (Throwable t) {
-			Thread.getDefaultUncaughtExceptionHandler().uncaughtException(null, t);
+			TiApplication.handleInternalException(t);
 		}
 
 		return false;

android/titanium/src/java/org/appcelerator/titanium/TiApplication.java

@@ -95,6 +95,7 @@ public abstract class TiApplication extends Application implements KrollApplicat
 	private String defaultUnit;
 	private BroadcastReceiver localeReceiver;
 	private AccessibilityManager accessibilityManager = null;
+	private UncaughtExceptionHandler nativeExceptionHandler = null;
 
 	protected TiDeployData deployData;
 	protected ITiAppInfo appInfo;
@@ -340,12 +341,23 @@ public void loadAppProperties()
 		}
 	}
 
+	public static void handleInternalException(Throwable throwable)
+	{
+		final UncaughtExceptionHandler currentExceptionHandler = Thread.getDefaultUncaughtExceptionHandler();
+		if (currentExceptionHandler != null) {
+			currentExceptionHandler.uncaughtException(Thread.currentThread(), throwable);
+		}
+	}
+
 	@Override
 	public void onCreate()
 	{
 		super.onCreate();
 		Log.d(TAG, "Application onCreate", Log.DEBUG_MODE);
 
+		// Reference to android run-time exception handler to delegate exceptions properly.
+		nativeExceptionHandler = Thread.getDefaultUncaughtExceptionHandler();
+
 		// handle uncaught java exceptions
 		Thread.setDefaultUncaughtExceptionHandler(new UncaughtExceptionHandler() {
 			@Override
@@ -364,6 +376,10 @@ public void uncaughtException(Thread t, Throwable e)
 
 				// throw exception as KrollException
 				KrollRuntime.dispatchException("Runtime Error", e.getMessage(), null, 0, null, 0, null, javaStack);
+
+				if (nativeExceptionHandler != null) {
+					nativeExceptionHandler.uncaughtException(t, e);
+				}
 			}
 		});
 

android/titanium/src/java/org/appcelerator/titanium/TiBaseActivity.java

@@ -790,7 +790,7 @@ public void onChanged(TiActivitySafeAreaMonitor monitor)
 		try {
 			windowCreated(savedInstanceState);
 		} catch (Throwable t) {
-			Thread.getDefaultUncaughtExceptionHandler().uncaughtException(null, t);
+			TiApplication.handleInternalException(t);
 		}
 
 		// set the current activity back to what it was originally
@@ -817,7 +817,7 @@ public void onChanged(TiActivitySafeAreaMonitor monitor)
 			try {
 				window.onWindowActivityCreated();
 			} catch (Throwable t) {
-				Thread.getDefaultUncaughtExceptionHandler().uncaughtException(null, t);
+				TiApplication.handleInternalException(t);
 			}
 		}
 		if (activityProxy != null) {
@@ -1338,7 +1338,7 @@ private void dispatchCallback(String propertyName, KrollDict data)
 			data.put(TiC.EVENT_PROPERTY_SOURCE, this.activityProxy);
 			this.activityProxy.callPropertySync(propertyName, new Object[] { data });
 		} catch (Throwable ex) {
-			Thread.getDefaultUncaughtExceptionHandler().uncaughtException(null, ex);
+			TiApplication.handleInternalException(ex);
 		}
 	}