- And via [Javadocs](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/)

- "[Intersection and overlap testing](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/com/badlogic/gdx/math/Intersector.html)"

- "[Immediate mode rendering](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/com/badlogic/gdx/graphics/glutils/ImmediateModeRenderer.html) emulation"

First an [LwjglApplicationConfiguration](https://github.com/libgdx/libgdx/tree/master/backends/gdx-backend-lwjgl/src/com/badlogic/gdx/backends/lwjgl/LwjglApplicationConfiguration.java) is instantiated. This class lets one specify various configuration settings, such as the initial screen resolution, whether to use OpenGL ES 2.0 or 3.0 and so on. Refer to the [Javadocs](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/backends/lwjgl/LwjglApplicationConfiguration.html) of this class for more information.

The main entry-point method is the Activity's `onCreate()` method. Note that `MainActivity` derives from `AndroidApplication`, which itself derives from `Activity`. As in the desktop starter class, a configuration instance is created ([AndroidApplicationConfiguration](https://github.com/libgdx/libgdx/tree/master/backends/gdx-backend-android/src/com/badlogic/gdx/backends/android/AndroidApplicationConfiguration.java)). Once configured, the `AndroidApplication.initialize()` method is called, passing in the `ApplicationListener` (`MyGdxGame`) as well as the configuration. Refer to the [AndroidApplicationConfiguration Javadocs](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/backends/android/AndroidApplicationConfiguration.html) for more information on what configuration settings are available.

An application developer hooks into these life-cycle events by implementing the [ApplicationListener](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/com/badlogic/gdx/ApplicationListener.html) interface and passing an instance of that implementation to the `Application` implementation of a specific back-end (see [The Application Framework](/wiki/app/the-application-framework)). From there on, the `Application` will call the `ApplicationListener` every time an application level event occurs. A bare-bones `ApplicationListener` implementation may look like this:

One can also derive from the [ApplicationAdapter](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/com/badlogic/gdx/ApplicationAdapter.html) class, which provides empty default implementations for those methods.

* Are you using the latest [nightly build](https://libgdx.badlogicgames.com/download.html)? Please try that first, as issues are being fixed every single day.

* Have you read the documentation on the [Table of Contents](/wiki/index)? It can also be very helpful to look at the [Javadocs](https://libgdx.badlogicgames.com/nightlies/docs/api/) and [source code](https://github.com/libgdx/libgdx) (don't be shy!). Search the [tests](https://github.com/libgdx/libgdx/tree/master/tests/gdx-tests/src/com/badlogic/gdx/tests) for a specific class to find example code.

We want fine grained control over the life-time of our resources. There are multiple classes in libGDX which represent such resources. They all implement a common [Disposable](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Disposable.html) interface which indicates that instances of this class need to be disposed of manually at the end of the life-time. **Failure to dispose resources will lead to severe memory leaks!**

The following classes need to be disposed of manually (might not be complete, [click here](https://libgdx.badlogicgames.com/ci/nightlies/docs/api/com/badlogic/gdx/utils/Disposable.html) instead for the full list):

* [Poolable](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Pool.Poolable.html) interface

* [Pool](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Pool.html)

* [Pools](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Pools.html)

The [Pools](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Pools.html) class provides static methods for dynamically creating pools of any objects (using [ReflectionPool](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/ReflectionPool.html) and black magic). In the above example, it could be used like this.

A `Pool<>` manages a single type of object, so it is parameterized by that type. Objects are taken from a specific `Pool` instance by invoking `obtain` and then should be returned to the Pool by invoking `free`. The objects in the pool may optionally implement the [`Pool.Poolable`](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Pool.Poolable.html) interface (which just requires a `reset()` method be present), in which case the `Pool` will automatically reset the objects when they are returned to the pool. By default, objects are initially allocated on demand (so if you never invoke `obtain`, the Pool will contain no objects). It is possible to force the `Pool` to allocate a number of objects by calling `fill()` after instantiation. Initial allocation is useful to have control over when these first time allocations occur.

All access to the audio facilities is done through the [audio module](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/Audio.html), referenced by:

The audio hardware is abstracted via the [AudioDevice](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/audio/AudioDevice.html) [(source)](https://github.com/libgdx/libgdx/blob/master/gdx/src/com/badlogic/gdx/audio/AudioDevice.java) interface.

You can access PCM data from the microphone on a PC or Android phone via the [AudioRecorder](https://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/audio/AudioRecorder.html) [(code)](https://github.com/libgdx/libgdx/blob/master/gdx/src/com/badlogic/gdx/audio/AudioRecorder.java) interface. To create an instance of that interface use: