Excessive garbage collection (GC_FOR_MALLOC) in Android emulator when using simpleframework

Question

I have an Android app that uses the SimpleFramework for XML serialization. The app runs fine on all real devices I have tested it on with no lags, but when run on the emulator, the garbage collector kicks in a runs for about about 3 minutes on each launch of the app.

Here is what I have observed so far:

• Garbage collection kicks in just before serializing objects to XML
• It only happens before the first object is serialized and sent over the network, and does not happen for successive calls.
• Serialization code is in a separate library that is packaged and added as a .jar file in the project.

Here is the output from LogCat:

07-27 08:17:10.275: D/dalvikvm(682): GC_FOR_MALLOC freed 10179 objects / 482344 bytes in 32ms
07-27 08:17:10.435: D/dalvikvm(682): GC_FOR_MALLOC freed 13927 objects / 535968 bytes in 33ms
....... About 300 more similar entries...

Here is the code I'm presently using for serialization:

public String fromElement(Object request) {
    Writer writer = new StringWriter();
    try {
        serializer.write(request, writer);
        String res = writer.toString();
        Log.d(LOG_TAG, res);
        return writer.toString();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return "";
}

Obviously, this is taking up a lot of time, each time I make a change in my code and redeploy the app. Has anyone else experienced this when using the libaray, and if so, is there some way I can prevent the GC from kicking in each time I launch the app (from eclipse)? Would increasing the heap (currently set at vm.heapSize=24) help? Or is there a different solution?

Answer 1

You need to upgrade to 2.6.7, there are pretty major changes to now annotation processing is done. It turns out Android has a fairly well know problem with annotations, relating strangely enough to a bad java.lang.reflect.Method.equals(Object) implementation. Simple 2.6.7 caches much more of the annotation processing and should be much better.