Google Maps API causing memory leaks?

Question

I just started using the Eclipse Memory Analyzer to try to solve a memory leak in my activity that extends MapActivity, but I am not sure if I understand its output correctly. In order to analyze the leak I started the activity and rotate the screen a couple of times and then I took a heap dump and opened it. The first thing I did was opening the Histogram view and look for my activity (called ChangeLocationActivity). This looks indeed like a memory leak, since there are three instances of the same Activity. So I got the list of objects with incoming references, then got the "Path to GC Roots" excluding weak references for all the three instances. This is the path of the first instance, this for the second instance (that custom MyLocationOverlay is a really simple class created to bypass a bug on some Motorola devices and it doesn't anything special apart from catching an Exception in drawMyLocation()) and finally this is the one for the third instance, which looks like the one currently shown.

As I said before I am not sure if I understand these results correctly (the Eclipse Memory Analyzer is really powerful but quite complex) but from what I can tell it looks like what's causing the memory leak is something related to the Google Maps library. Can anyone tell me if I am right or if I'm just not understanding these results?

Answer 1

Select all the activities and use "Merge Shortest Paths to GC Roots". Post the result here. Your second Activity seems to be alive because you registered an EventListener.

"Merge Shortest Paths to GC Roots" is one of the more important commands in MAT. It shows to all the pathes for objects to roots but merges them and therefore allows you to analyze which objects are still alive because they share the same pathes. From your screenshot (please expand the 3 subtrees) it seems your 3 activties are hold be 3 root objects. It is typical for leaks that the share some common objects along their merged root paths. Typically from what I've seen in your case you have more than one reason for the leak, because each activity is hold by a different root object. I would recommend to try to get as many activities to be leaked as possible by repeating the test.

Regards, Markus