# Create and use plug-ins in Android

> Describes the plug-in types you can use in Android and explains how to build and use them.

You can use plug-ins to deliver resources and call Java and C++ code created outside of Unity from your C# scripts. They enable you to access features, like third-party code libraries and operating systems calls, that would otherwise not be available to Unity. For more information about plug-ins with Unity, see [Plug-ins](/engine/6000.3/manual/scripting/compilation-and-code-reload/plug-ins.md).

This section describes how to create your own plug-ins and use them in Android projects. The information on these pages assumes you already know how to create native plug-ins for Unity. For more information about native plug-ins and their uses, see [Native plug-ins](/engine/6000.3/manual/scripting/compilation-and-code-reload/plug-ins/native.md).

| **Topic**                                                                                                                                                           | **Description**                                                                  |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- |
| [Android plug-in types](/engine/6000.3/manual/platform-specific/android/developing/plugins-for/plugin-types.md)                                                     | Understand the different plug-in types available for Unity Android applications. |
| [Calling Java and Kotlin plug-in code from C# scripts](/engine/6000.3/manual/platform-specific/android/developing/plugins-for/plugins-java-code-from-c-sharp.md)    | Interact with Java and Kotlin plug-in code from your C# scripts.                 |
| [Calling C# code from Java and Kotlin plug-in code](/engine/6000.3/manual/platform-specific/android/developing/plugins-for/plugins-csharp-code-from-java-kotlin.md) | Access your C# scripts from Java and Kotlin plug-in code.                        |

## Unity as a Library

If you upgrade your project to Unity 2019.4 or above, the introduction of Unity as a Library might require you to adapt your [native](/engine/6000.3/manual/scripting/compilation-and-code-reload/plug-ins/native.md) and [managed](/engine/6000.3/manual/scripting/compilation-and-code-reload/plug-ins/managed.md) plug-ins to work properly for Android.