java.util.ConcurrentModificationException

[hammadrfq3]

I am getting this exception on notifyListenersComplete patternLockView class

Fatal Exception: java.util.ConcurrentModificationException: at java.util.ArrayList$Itr.next(ArrayList.java:860) at com.andrognito.patternlockview.PatternLockView.notifyListenersComplete(PatternLockView.java:751) at com.andrognito.patternlockview.PatternLockView.notifyPatternDetected(PatternLockView.java:719) at com.andrognito.patternlockview.PatternLockView.handleActionUp(PatternLockView.java:1052) at com.andrognito.patternlockview.PatternLockView.onTouchEvent(PatternLockView.java:445) at android.view.View.dispatchTouchEvent(View.java:13488) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3088) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2781) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3088) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2781) at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3088) at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2781) at android.view.View.dispatchPointerEvent(View.java:13749) at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5616) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5416) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4917) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4970) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4936) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:5076) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4944) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:5133) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4917) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4970) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4936) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4944) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4917) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7669) at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7638) at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7599) at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7797) at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:251) at android.os.MessageQueue.nativePollOnce(MessageQueue.java) at android.os.MessageQueue.next(MessageQueue.java:336) at android.os.Looper.loop(Looper.java:181) at android.app.ActivityThread.main(ActivityThread.java:7592) at java.lang.reflect.Method.invoke(Method.java) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)