Deep Dive into Android Heap Dumps: Advanced Techniques for Optimizing Memory
Keep control of your app's memory requirements
Android developers are on the cutting edge of technology’s trend towards smaller, faster and cheaper. To remain competitive in today’s app market, we need to constantly challenge ourselves to make the best use of limited resources to provide faster, richer user experiences.
Excess memory usage not only degrades performance, but can cause unreliability and out of memory crashes. Android memory analyzers let us make sure we’re making the best use of valuable resources. In this article, we’ll look at how to use a heap dump to evaluate memory usage, and best practices for keeping RAM requirements to a minimum.
How Much Memory is Available for Android Apps?
Although each new version of Android supports more RAM, it’s still very limited compared to large servers or even laptops.
A mid-range Android released in 2025 may have around 8GB of memory, but not much of this is available for user applications. Typically, memory usage can be summarized as shown in the table below.
Android Memory Usage | |
Component | GB |
Android Operating System | 1.8 |
System User Interface | 0.5 |
Preloaded & Background Apps | 2.8 |
Graphics Cache | 0.3 |
Services | 0.6 |
Total | 6.0 |
Available for Apps | 2.0 |
The available memory must be shared between whichever applications are open at a given time.
Using an Android Memory Analyzer With Heap Dumps
A heap dump is a snapshot of heap memory at a given moment. Since it’s a large binary file, we need an Android memory analyzer such as HeapHero or Eclipse MAT to retrieve meaningful information from it.
See this article: How to Take a Heap Dump in Android to see a few different ways of obtaining the heap dump. We can then load the dump file into a memory analyzer.
HeapHero can either be used in the cloud or on-premise. It produces a comprehensive, interactive report, showing exactly what objects are loaded in memory and how much space they’re occupying.
If HeapHero detects an obvious memory leak or other serious issues, it will include recommendations at the front of the report.
The best place to start is to look at the Largest Objects section, as shown in the image below.
Fig: Largest Objects
If there is a memory leak, it’s likely to be caused by one of the top four items on the list.
From this report we can see exactly how much memory is used by each object.
We can also browse through the objects to find the parents and children of each, and see how much memory they’re using.
HeapHero also detects any areas where memory is wasted, and produces a detailed report. In the section of the report below, we can see that the program is wasting 57KB by using inefficient collections.
Fig: Inefficient Collections
It includes a histogram showing the number of instances of each class:
Fig: Class Histogram
This can be helpful if the program is creating an excessive number of objects of the same class.
Typical Causes of Wasted Memory
Here are some areas that can be tightened up if an application is using too much memory.
Variables Not Declared in the Correct Scope: If variables are declared outside the block where they’re actually used, the garbage collector won’t be able to remove them in a timely manner.
Resources Not Released When No Longer Needed: Always use an object’s close or cleanup methods if it has them. Set objects to null if they’re no longer needed.
Finalizer Methods Taking Too Long to Complete: If a finalizer method hangs waiting for resources, it can disrupt the entire garbage collection process.
Duplicate Strings, Arrays and Objects: Many programs hold the same information in many different places.
Inefficient Collections and Arrays: Programmers should plan the size of arrays properly to fit requirements. Be aware of the initial size of collections, and the amount by which they grow when they exceed their current size.
Boxed Numbers: When possible, use primitives such as int rather than objects such as Integer. Every object has a 12 byte overhead for the object header, and this can add up to a large amount of wasted space.
For more information, see this article: How Much Memory is My Application Wasting?.
Conclusion
When developing for Android, it’s essential to be constantly aware of how much memory the app will use, since resources are limited. An efficient Android memory analyzer can help you develop leaner, meaner apps that will outshine your competitors.
