How important is setting environment variables in Java?

Question

I am writing a blog where I have explain my students how to install Java, but I'm wondering why should expose them to this complicated part of Java installation. When I used Java before, I used right out of the box with my IDE. But all the tutorials I see mention configuration of these environment variables.

Maybe my PATH variables were set from previous installations, however I don't remember doing it.

Can anyone please advise if environment variable setting can be left to the IDEs or has to be done manually?

Answer 1

Java does not need any environment variables to be set.

However, setting some environment variables makes some things easier.

• PATH If the jre/bin folder is on the path, you don't have to qualify to run the java command. If the jdk/bin folder is on the path, you don't have to qualify to run the java and javac commands. As well as some other commands provided by Java.

• JAVA_HOME Used by many Java programs and installers to find Java.

When using an IDE, it can usually find / prompt for Java installations, so it doesn't need any environment variables. The IDE won't set them either.

Answer 2

As mentioned above, JAVA_HOME Used by many Java programs and installers to locate Java. for instance, Tomcat requires the environment variable JAVA_HOME to be set to the JDK installed directory.

To check if JAVA_HOME is already set, start a terminal and issue:

echo $JAVA_HOME

JAVA_HOME is to be set to the JDK installed directory. You need to find your JDK installed directory.

[TODO] find macOS and Ubuntu JDK installed directory.

Add the the following line at the end of "~/.bashrc" (or "~/.login"). Take note that filename beginning with dot (.) is hidden by default.

[TODO] How to un-hide for macOS/Ubuntu.

export JAVA_HOME=/path/to/JDK-installed-directory


// Verify the new setting
echo $JAVA_HOME