Android Manifest

From Altilunium

A XML file that define the whole Android App structure.

Overall Structure

  • xml
  • manifest
    • uses-sdk
    • uses-feature
    • uses-permission
    • application
    • queries

Application

  • activity
  • receiver
  • provider
  • service
  • uses-library

Features

Enable Large Heap

<application android:largeHeap="true">

Too many Java objects in your app may cause java.lang.OutOfMemoryError. As a quick-fix, you can force the Dalvik VM to increase the heap memory-size by enabling largeHeap="true". But in the end, it's still limited to the device's actual available RAM though. Android official documentation doesn't really state how large the additional heap is, but they offered some hint regarding the maximum available size, which is 16 MB or more.

From baeldung.com (Java guides and course provider) :

  • New objects are created in heap space.
  • If heap space is full, Java throws java.lang.OutOfMemoryError
  • Isn't automaticaly deallocated. It needs Garbage Collector.
  • All new objects are allocated and aged in young generation. A minor garbage collection occurs when this fills up. When new objects are stored in the young generation, a threshold for the object's age is set. When that threshold is reached, the object is moved to the old generation

From oracle.com :

  • Java objects reside in the heap. The heap is created when the JVM starts up and may increase or decrease in size while the applications runs. When the heap becomes full, garbage is collected.
  • The heap is divided into two areas, called the nursery (young space) and the old space. The nursery is a part of the heap reserved for allocation of new objects. When the nursery becomes full, garbage is collected by running a special "young collection", where all objects that have lived long enough in the nursery are "promoted" to the old space. The reasoning behind a nursery is that most objects are temporary and short lived.

From developer.android.com :

  • android:largeHeap : Whether your application's processes should be created with a large Dalvik heap. This applies to all processes created for the application. To query the available memory size at runtime, use the methods getMemoryClass
  • public int android.app.ActivityManager.getMemoryClass() : Return the approximate per-application memory class of the current device. The returned values is in megabytes. The baseline Android memory class is 16 (Java heap limit of those devices). Some devices with more memory may return 24 or even higher number.