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Configure Java for Android

If you are building Android via the command line (which includes our recommended pre-push hooks), you will need to configure Java. If not, you can just use Android Studio and do not need to read further.

Notes:

  • this guide is written using macOS and will need to be updated to additionally support Linux and Windows.
  • if you find a better way to do configure Java, let us know!

Background

At the time of writing, Android development seems to work best when using Java 8. By default brew and other package managers will install more recent versions that may throw errors during development.

Caveat: Robolectric warns that Java 9 is needed for certain functionality. This seems inconsistent with the rest of the Android ecosystem, however.

Methods

Method #1: configure Java 8 from Android Studio

Do the following:

  • Download and install Android Studio
  • Add the following line to your ~/.zshrc or equivalent shell startup file: export JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home"
    • Update the path if you installed Android Studio to a non-standard location

That's it! To verify correctness, open a new shell, navigate to a directory with Android source code, and type ./gradlew tasks.

This works because macOS comes with a /usr/bin/java stub which will defer the location of the JDK to the value in the JAVA_HOME environment variable.

Method #2: install Java 11 from Homebrew

You can install Java from Homebrew using the command below.

brew install java11

Method #3: install from website

You can install Java from Oracle using this link.

Installing the JDK:

  • Navigate to Java SE Development Kit 8u341 and click macOS.
  • Download the package named jdk-8u341-macosx-x64.dmg. Oracle requires you to make an account in order to install the JDK. Follow the instructions and confirm your email.
  • Launch your .dmg installer and follow the installation wizard.
  • Add the following line to your ~/.zshrc or equivalent shell startup file: export JAVA_HOME=$(/usr/libexec/java_home)

That's it! To verify correctness, open a new shell, navigate to a directory with Android source code, and type ./gradlew tasks.

As explained in Method #1, $JAVA_HOME is the environment variable in UNIX environments that points to your JDK installation. /usr/libexec/java_home is a symbolic link that points to matching Java VMs installed in your environment.

If you are having trouble, please make sure to read this Java Doc on how to install Java on your machine. Although this documentation highlights how to install the JRE, installing the JDK follows the same steps.

Troubleshooting

Get Java version

To see what version of Java you have installed, run:

java -version

If you have Java 8 configured, you'll see output like:

openjdk version "1.8.0_242-release"
OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
OpenJDK 64-Bit Server VM (build 25.242-b3-6222593, mixed mode)

Error running pre-push hooks

If you encounter this error, particularly when running our recommended pre-push hooks:

Could not initialize class org.codehaus.groovy.runtime.InvokerHelper

You may be on Java 14: consider installing Java 8 (see above). If preferred, other users have found installing any version of Java, 13 or lower, appears to resolve the issue:

Steps to downgrade Java Version on Mac with Brew:

  1. Install Homebrew (https://brew.sh/)
  2. run brew update
  3. To uninstall your current java version, run sudo rm -fr /Library/Java/JavaVirtualMachines/<jdk-version>
  4. run brew tap homebrew/cask-versions
  5. run brew search java
  6. If you see java11, then run brew install java11
  7. Verify java-version by running java -version