Ubuntu Java Linux
Update apt-get package index:
$ sudo apt-get update
Install the jre:
$ sudo apt-get install openjdk-8-jre
Check Java version
$ java -version
openjdk version "1.8.0_121"
OpenJDK Runtime Environment (build 1.8.0_121-8u121-b13-0ubuntu1.16.04.2-b13)
OpenJDK 64-Bit Server VM (build 25.121-b13, mixed mode)
To find the JRE location:
$ whereis java
java: /usr/bin/java /usr/share/java /usr/share/man/man1/java.1.gz
Now see what's in /usr/bin/java
$ ls -l /usr/bin/java
lrwxrwxrwx 1 root root 22 Apr 2 13:36 /usr/bin/java -> /etc/alternatives/java
As seen, the real location of the symbolic link '/usr/bin/java' is the right side of ->
Now see what's there:
$ ls -l /etc/alternatives/java
lrwxrwxrwx 1 root root 46 Apr 2 13:36 /etc/alternatives/java -> /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
so the root location of jre is /usr/lib/jvm/java-8-openjdk-amd64/jre/
Note that we can also use following to find jre location:
$ sudo update-alternatives --config java
Now we are going to set Java home environmental variable with the jre location we just found.
$ sudo nano /etc/environment
In nano editor add new line:
JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64/jre"
Save and exit.
To load our new env variable:
$ source /etc/environment
Now check it out:
$ echo $JAVA_HOME
/usr/lib/jvm/java-8-openjdk-amd64/jre
|