bash saya

# Download Linux x64 185.16 MB jdk-8u231-linux-x64.tar.gz dari sini.
$ sudo mkdir -p /opt/jdk
$ sudo cp -rf jdk-8u231-linux-x64.tar.gz /opt/jdk
$ cd /opt/jdk
$ sudo tar -zxf jdk-8u231-linux-x64.tar.gz
$ sudo update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.8.0_231/bin/java 100
$ vim /etc/environment
$ cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
JAVA_HOME=/opt/jdk/jdk1.8.0_231
JRE_HOME=/opt/jdk/jdk1.8.0_231/jre
$  source /etc/environment
$ echo $JAVA_HOME
/opt/jdk/jdk1.8.0_231
> $ echo $JRE_HOME
/opt/jdk/jdk1.8.0_231/jre