Unity supports plug-insA set of code created outside of Unity that creates functionality in Unity. There are two kinds of plug-ins you can use in Unity: Managed plug-ins (managed .NET assemblies created with tools like Visual Studio) and Native plug-ins (platform-specific native code libraries). More info
See in Glossary for Android written in Java or Kotlin. This functionality allows you to add .java or .kt files into your Unity Project and they are compiled when you build an Android Player. Previously, you had to precompile these files as an Android library.
To compile the source files as a plug-in, follow these steps:
Note: You can place your source files in any folder in your Project except in special use locations such as StreamingAssets. If you place files in these locations, the Unity Editor will not display the plug-in inspector. For additional information, see AAR plug-ins and Android Libraries.
Use the AndroidJavaObject class to call methods in your plug-in. For additional information see, the “Using your Java plug-in from C# scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
See in Glossary with helper classes” section in JAR plug-ins.
To enable direct referencing of the Java and Kotlin files in the exported gradleAn Android build system that automates several build processes. This automation means that many common build errors are less likely to occur. More info
See in Glossary project and eliminte the need to manually copy the edited Java and Kotlin files from the exported gradle project to the Unity Project, enable Symlink Sources in the Build Settings window.