Hi,
Firstly thank you for your time.
Sometimes, logback does not print exception's cause, I can't use the log to fix bug, as followings:
2020-06-09 16:54:32,393 ERROR [task-executor-27] [SimpleDispatcher.java:203] Exception occurred during dispatch web socket frame for uri[/ws/partydungeon/move] by uid[6493203].
java.lang.reflect.InvocationTargetException: null
at sun.reflect.GeneratedMethodAccessor100.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.mitu.game.dispatcher.SimpleDispatcher$EventRunnable.doWebSocketMessage(SimpleDispatcher.java:187)
at com.mitu.game.dispatcher.SimpleDispatcher$EventRunnable.run(SimpleDispatcher.java:106)
at com.mitu.game.wrapper.ThreadPoolTaskExecutorEx$SafeRunnable.run(ThreadPoolTaskExecutorEx.java:74)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException: null
And the code is like:
private void doWebSocketMessage(Event event) {
String uri = "some uri";
String uid = "some id";
try {
Object ret = action.method.invoke(
action.instance, event.getData(), new Object[]{event});
} catch (Exception ex) {
logger.error(String.format("Exception occurred during dispatch web socket frame for uri[%s] by uid[%s].", uri, uid), ex);
}
}
I tried to look for answers by google and bing, but failed, and I tried to reproduce this problem, failed too, the cause can be printed, and it likes:
java.lang.reflect.InvocationTargetException: null
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.mitu.game.Application.main(Application.java:54)
Caused by: java.lang.NullPointerException: null
at com.mitu.game.Application$T.f(Application.java:42)
... 5 common frames omitted
the difference is NativeMethodAccessorImpl vs GeneratedMethodAccessor100, is it matter? I steped into the logback code, maybe the target of the exception is null, but I do not know the reason:(
Thank you again, for your patient, and sorry for my poor english:(
BR,
Mike Yu