* A [Java Development Kit](http://jdk.java.net/) (JDK) **version 11**. Fixed version is required to use [remote cache](#remote-build-cache). 
* A text editor or IDE. We use and recommend [IntelliJ IDEA CE](http://www.jetbrains.com/idea/).  IntelliJ Ultimate will also work. You'll need IntelliJ 2021.2.2 or newer.
* [git](https://git-scm.com/) and a [GitHub account](https://github.com/join).

If you've found a security problem, please follow our [bug bounty][security] program.

If you've found a bug, please contribute a failing test case so we can study and fix it.

If you have a new feature idea, please build it in an external library. There are
[many libraries][works_with_okhttp] that sit on top or hook in via existing APIs. If you build
something that integrates with OkHttp, tell us so that we can link it!