Introduction of The Android Application Class in Android

Your application’s Application object remains instantiated whenever your application runs. Unlike Activities, the Application is not restarted as a result of configuration changes. Extending the Application class with your own implementation enables you to do three things:

  • Respond to application level events broadcast by the Android run time such as low memory conditions
  • Transfer objects between application components.
  • Manage and maintain resources used by several application components

Of these, the latter two can be better achieved using a separate singleton class. When your Application implementation is registered in the manifest, it will be instantiated when your application process is created. As a result, your Application implementation is by nature a singleton and should be implemented as such to provide access to its methods and member variables.

Extending and Using the Application Class

import android.content.res.Configuration;
public class MyApplication extends Application {
 private static MyApplication singleton;
 // Returns the application instance
 public static MyApplication getInstance() {
 return singleton;
 public final void onCreate() {
 singleton = this;

When created, you must register your new Application class in the manifest’s application node using a name attribute

<application android:icon=”@drawable/icon”
 [... Manifest nodes ...]

Your Application implementation will be instantiated when your application is started. Create new state variables and global resources for access from within the application components:

MyObject value = MyApplication.getInstance().getGlobalStateValue();

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