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performs tasks without providing an user interface.
They can communicate with other Android components and send notifications to the user.
An Android application can have several activities.
Activities use views and fragments to create their user interface and to interact with the user.
The first start may take long, e.g., several minutes on an older machine.A provider can be used for accessing data within one application, but can also be used to share data with other applications.Android contains an SQLite database which is frequently used in conjunction with a content provider.If not explicitly defined, Android creates a default application object for your application.An activity is the visual representation of an Android application.