If you have XCode installed you can now find the JAVA_HOME directory with this command: I have no way of verifying this any more, but on Mac OS X 10.5, 10.6, and 10.7, I'm pretty sure this is where the JDK JAVA_HOME was located: Library/Internet\ Plug-Ins/ugin/Contents/Home/bin/java -version Older Mac OS X systems This is confirmed by this Oracle Java/JRE documentation page, which shows that you can demonstrate this by running this command in the Mac Terminal: Library/Internet Plug-Ins/ugin/Contents/Home If you've installed the Oracle JRE (as opposed to the JDK), JAVA_HOME for it appears to be located here instead: Of course that will vary by the JDK version you have installed. Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home/
Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home This has changed over time, but if you're using Mac OS X 10.9 or newer (now macOS), your JDK/SDK JAVA_HOME location for Java 8 will be something like this:
Java/Mac FAQ: Where is JAVA_HOME located on Mac OS X (macOS) systems? macOS JDK location