Is it possible to setup 2 JAVA_HOME in Linux?

Question

I am using RHEL 6.8. Is it possible to set up a 1.8 server JRE path in JAVA_HOME in Linux when the JDK is 1.7.0_45? I need both of the java versions and two JAVA_HOME.

Thanks in advance!

Answer 1

The typical way to handle such things is by using alternatives.

Meaning: it is absolutely no problem to have multiple JREs/JDKs on the same system; you just need to manage them; and alternatives helps with that.

For Redhat, have a look into their documentation.

Answer 2

You can have 2 version but you can use only one at a time or create 2 system user with different profile as mentioned below:

/usr/local/java/ - jdk1.8.0_60 - jre1.7.0_60

1) vim ~/.profile or vim ~/.bash_profile

2) Add below lines at end. Please check your jdk/jre path and change it accordingly 
export JAVA_HOME=/usr/local/java/jre1.7.0_60
export PATH=$JAVA_HOME/bin:$PATH

3) exit vim editor

4) echo $JAVA_HOME

you will require to logout from system and login again.

if you want to switch it to jdk1.8.0_60 then edit the same file ~/.profile or ~/.bash_profile and follow the above procedure again.

Answer 3

You can't really have two JAVA_HOME environmental variables in the same Linux environment (the env variables are basically key-value entries, thus you can't have to entries with the same key JAVA_HOME).

I suggest the solution I wrote here: https://stackoverflow.com/a/50766853/6661361

In few words:

1. Install all your java alternatives:

   sudo update-alternatives --install /usr/bin/java java /home/aqeel/development/jdk/jdk1.6.0_35/bin/java 1`
   

2. Add the following snippet to your ~/.bashrc (or other bash configuration file, depending on the scope you want to use):

   export JAVA_HOME=$(update-alternatives --query java | grep Value: | awk -F'Value: ' '{print $2}' | awk -F'/bin/java' '{print $1}')
   

3. Choose you java version with the following command:

   sudo update-alternatives --config java
   

   Your JAVA_HOME should change automatically (just remember to open a new command terminal after changing the java version, or create a script to do it manually).

4. Optionally: if you have to change the java version constantly, you might want to consider adding an alias to your ~./bash_aliases:

   alias change-java="sudo update-alternatives --config java"
   

(You might have to create the file and maybe uncomment the section related to this in ~/.bashrc).