Exceptions that look like this are confusing:
FATAL EXCEPTION: main
java.lang.NullPointerException
at android.os.Parcel.readException(Parcel.java:1437)
at android.os.Parcel.readException(Parcel.java:1385)
at com.yourpackage.ipc.IYourClass$Stub$Proxy.yourMethod(IYourClass.java:488)
at com.yourpackage.ipc.YourClassShim.yourMethod(YourClassShim.java:269)
I found a bunch of related questions for this, but none with the answer to "how do you debug this". So I'm making this Question/Answer.
By looking at the android source here and here you'll see that it can be throwing any of these (the NullPointerException is just what I had):
SecurityException(msg);
BadParcelableException(msg);
IllegalArgumentException(msg);
NullPointerException(msg);
IllegalStateException(msg);
RuntimeException("Unknown exception code: " + code + " msg " + msg);
But what's causing these?
What's going on here is that readException()
is checking the IPC byte stream for a header that says that an exception occurred; if it finds one, then it throws a new exception of that type, with the same message, but missing the original stack trace. (It only actually knows a few exception types; anything else gets translated into a base RuntimeException
.)
So where's the original exception coming from? Well, somewhere down in the guts of the real implementation of YourClass.yourMethod()
-- not in any of the parcelable or IPC code. So go there, wrap the whole method in a try/catch, and log whatever you caught.
(Or set a breakpoint there if you've got remote process breakpoints working.)
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