How to set java home in Linux

Open terminal on Linux box

Type the following commands.
Please note change the directory names as per your machine

export JAVA_HOME=/opt/java/jdk1.7.0_79/   
export JRE_HOME= /opt/java/jdk1.7.0_79/jre    
export PATH=$PATH:/opt/java/jdk1.7.0_79/bin:/opt/java/jdk1.7.0_79/jre/bin

Alternatively goto user home directory ( /home/oracle)

Type ls -a

This will list the .bash_profile file

open the .bash_profile using  vi  .bash_profile

add the following lines to .bash_profile

export JAVA_HOME=/opt/java/jdk1.7.0_79/   
export JRE_HOME= /opt/java/jdk1.7.0_79/jre    
export PATH=$PATH:/opt/java/jdk1.7.0_79/bin:/opt/java/jdk1.7.0_79/jre/bin

save the file

Now source the ./bash_profile

source .bash_profile