find-java-home

In this quick post, we’ll learn how to find JAVA_HOME on Windows, Mac, and Linux.

As we all know, JAVA_HOME is an environment variable that we commonly use to locate java executables like java and javac.

If we’re using Windows as the operating system, first we need to open up our command line (cmd) and type:

If JAVA_HOME is defined in our environment, then the above command will print it out.

Or, we could try:

Which will show the location of the java executable.

If we’re using either macOS or Linux, we can open up our terminal and type:

If JAVA_HOME is defined in our environment, then the above command will print it out.

Or, we could try:

Which probably just shows us /usr/bin/java.

But, really this isn’t very helpful since it’s a symbolic link. To unravel this, we’ll use dirname and readlink;

for Linux:

and for macOS:

As a result, this command prints the currently used java folder.

And, if we’re able to run java ourselves, then we have a nearly platform-independent way, too:

Running this command outputs numerous properties, one of them being java.home.

To parse it, though, we’ll still need a platform-specific tool.

For Linux and macOS, let’s use grep:

And for Windows, let’s use findstr:

With this quick post, we’ve learned how to find JAVA_HOME on different operating systems.

If they didn’t work, though, maybe we didn’t set JAVA_HOME variable properly while installing Java.