How to set JAVA_HOME in Linux for all users

Question

I am new to Linux system and there seem to be too many Java folders.

java -version gives me:

• java version "1.7.0_55"
• OpenJDK Runtime Environment (rhel-2.4.7.1.el6_5-x86_64 u55-b13)
• OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)

When I am trying to build a Maven project , I am getting error:

Error: JAVA_HOME is not defined correctly.

We cannot execute /usr/java/jdk1.7.0_05/bin/java

Could you please tell me which files I need to modify for root as well as not-root user and where exactly is java located?

Answer 1

1. find /usr/lib/jvm/java-1.x.x-openjdk

2. vim /etc/profile

   Prepend sudo if logged in as not-privileged user, ie. sudo vim

3. Press 'i' to get in insert mode

4. add:export JAVA_HOME="path that you found"

   export PATH=$JAVA_HOME/bin:$PATH

5. logout and login again, reboot, or use source /etc/profile to apply changes immediately in your current shell

Answer 2

To resolve the JAVA_HOME issue and build your maven projects on your Linux system. you need to check the correct Java installation path. 

The following command will list all the directories containing Java Runtime Environments under path "/usr/lib/jvm"

Command: "find /usr/lib/jvm -name jre1.* -type d"

From the list select the desired Java version and select the path that you want to use for Java installation.

To set JAVA_HOME for all users:

• Edit the “/etc/environment” file: sudo nano /etc/environment
• Add the following line to the end of the file, that replaces the environment with the actual path: JAVA_HOME="/usr/lib/jvm/java-11-openjdk-11.0.18+10-1.el8_6.x86_64/"
• Now Save the file before closing it.

Finally, update the environment variables by running the

command: sudo source /etc/environment

Open a new terminal and run to verify the JAVA_HOME setting: echo $JAVA_HOME

This should display the path you set in the /etc/environment file.c

Create a Maven project build, The JAVA_HOME error should be resolved.