aidl로 매서드 하나 추가해서 사용하려고 하는데 아래와 같은 에러가 발생하네요.
아래의 붉은색 부분에서 실제 Exception이 발생하는데, 실제 string을 전달하려고 합니다. 추가한 매서드 전에 string은 정상적으로 값을 갖고 있는 상태이며, 추가한 매서드를 통해 만들어진 out/../ISms.java파일의 _reply.readException(); 부분에서 null pointer Exception을 찍는것 같습니다. 무슨 문제인지 도움을 구합니다.

android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
java.lang.String _result;
try {
_data.writeInterfaceToken(DESCRIPTOR);
_data.writeString(Address);
mRemote.transact(Stub.TRANSACTION_setCallbackNum, _data, _reply, 0);
_reply.readException();
_result = _reply.readString();
}
finally {
_reply.recycle();
_data.recycle();
}
return _result;
01-07 10:47:22.993: WARN/dalvikvm(1359): threadid=3: thread exiting with uncaught exception (group=0x2aaca160)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359): Uncaught handler: thread main exiting due to uncaught exception
01-07 10:47:22.993: ERROR/AndroidRuntime(1359): java.lang.NullPointerException
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.os.Parcel.readException(Parcel.java:1224)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.os.Parcel.readException(Parcel.java:1206)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at com.android.internal.telephony.ISms$Stub$Proxy.setCallbackNum(ISms.java:447)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at com.android.mms.ui.MessagingPreferenceActivity.onPreferenceTreeClick(MessagingPreferenceActivity.java:304)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.preference.Preference.performClick(Preference.java:821)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.preference.PreferenceScreen.onItemClick(PreferenceScreen.java:190)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.widget.AdapterView.performItemClick(AdapterView.java:284)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.widget.ListView.performItemClick(ListView.java:3285)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:1640)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.os.Handler.handleCallback(Handler.java:587)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.os.Looper.loop(Looper.java:123)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at android.app.ActivityThread.main(ActivityThread.java:4325)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at java.lang.reflect.Method.invokeNative(Native Method)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at java.lang.reflect.Method.invoke(Method.java:521)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
01-07 10:47:22.993: ERROR/AndroidRuntime(1359):     at dalvik.system.NativeStart.main(Native Method)