From the Google I/O 2011 video, Memory management for Android Apps by Patrick Dubroy. Also see Memory Analysis for Android Applications and Avoiding memory leaks by Romain Guy.



Integer value in MB which is the heap size for your application.

To get a larger heap size (only for memory intensive apps e.g. an image editor) put android:largeHeap into your AndroidManifest.xml. To find how much memory is available


Note: DO NOT USE ‘largeHeap’ AS A MATTER OF ROUTINE. It will not be good for your users when they try to run multiple applications, and garbage collection will take longer.


Log messages…

GC_CONCURRENT is triggered as heap starts to fill up.

GC_FOR_MALLOC when concurrent collection didn’t complete in time, so more memory had to be allocated by stopping and running garbage collection.

GC_EXPLICIT when manually calling garbage collection (don’t do this).

e.g. freed 2049K

Amount of memory freed on this collection

e.g. 65% free 3571K/9991K

65% free after collection completed. 3571K free after collection, 9991K total heap memory.

e.g. external 4703K/5261K

4703K externally allocated memory (bitmaps etc). 5261K is a soft limit where garbage collection will be started by the system.

e.g. paused 2ms+2ms

concurrent collections will show two pause times. Non concurrent show a single pause time (and will be higher).


Create a heap dump using DDMS by clicking on the Dump HPROF file icon in the IDE. There is also an API call if you need to create a dump at a specific time:


Only need to convert to HPROF format if using the stand-alone version of DDMS:

~/bin/adt-bundle-linux-x86_64/sdk/tools/hprof-conv orig.hprof converted.hprof

The heap can then be analysed using standard heap analysis tools (MAT, jhat etc)

Eclipse Memory Analyzer (MAT)

Shallow heap

How large is this object (size in bytes)

Retained heap

What other objects could be freed at the same time? Total size of objects which could be freed (check out the dominator tree concept)

Dominator Tree

List of objects organised by amount of Retained Heap.

Right click on an object, Path to GC Roots, exclude weak references

The analyser does not treat weak references separately. Generally do not need to be concerned with weak references.

Histogram View

byte[] are now the backing data for pixel data. Right click, List objects, with incoming references, Right click, Path to GC Roots, exclude weak references

If Objects shows more than one instance of your activity, then this is worth investigating.