GCM 관련! 익셉션 질문

Question

02-20 11:54:30.076: D/AndroidRuntime(27093): Shutting down VM
02-20 11:54:30.076: W/dalvikvm(27093): threadid=1: thread exiting with uncaught exception (group=0x418602a0)
02-20 11:54:30.076: E/AndroidRuntime(27093): FATAL EXCEPTION: main
02-20 11:54:30.076: E/AndroidRuntime(27093): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.gcmmanager/com.example.gcmmanager.GCMSendMessage}: java.lang.NullPointerException: println needs a message
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread.access$700(ActivityThread.java:140)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.os.Looper.loop(Looper.java:137)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread.main(ActivityThread.java:4946)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at java.lang.reflect.Method.invokeNative(Native Method)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at java.lang.reflect.Method.invoke(Method.java:511)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1036)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:803)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at dalvik.system.NativeStart.main(Native Method)
02-20 11:54:30.076: E/AndroidRuntime(27093): Caused by: java.lang.NullPointerException: println needs a message
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.util.Log.println_native(Native Method)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.util.Log.w(Log.java:225)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at com.example.gcmmanager.GCMSendMessage.getJson(GCMSendMessage.java:193)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at com.example.gcmmanager.GCMSendMessage.onCreate(GCMSendMessage.java:74)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.Activity.performCreate(Activity.java:5206)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
02-20 11:54:30.076: E/AndroidRuntime(27093):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
02-20 11:54:30.076: E/AndroidRuntime(27093):  ... 11 more
02-20 11:54:32.041: I/Process(27093): Sending signal. PID: 27093 SIG: 9

GCM을 구현하려구 찾던도중 딱 알맞은 예제 프로젝트가 있어서 테스트 해보려는데요.. 도저히 이 에러를 못잡겠습니다...

Nullpointer 라는데 어떻게 해야 하나요>

 

Answer 1

Log.w 에 넘겨지는 인자가 NULL 이라는 것 같은데요.

브레이크 포인터 걸어서 확인해보시면 될꺼 같네요.

Answer 2

E/AndroidRuntime(27093): Caused by: java.lang.NullPointerException: println needs a message

E/AndroidRuntime(27093):  at android.util.Log.println_native(Native Method)

E/AndroidRuntime(27093):  at android.util.Log.w(Log.java:225)

 

E/AndroidRuntime(27093):  at com.example.gcmmanager.GCMSendMessage.getJson(GCMSendMessage.java:193)

 

말씀하신데로 NullPointer에러가 나고 있습니다. NullPointer에러 발생시 그 아래있는 스택 내용을 차례차례 내려가면서 살펴보면 GCMSendMessage.java의 193라인에서 부터 시작된것을 알수가 있습니다. 그 부분 소스를 살펴보세요.