These are path to system and application binaries. You should not edit/overwrite them unless you know what you are doing.
I Assume Java is installed at /opt/java/jdk1.7.0_67/ directory. Change it as per your installation.
To set Java Path # export PATH=$PATH:/opt/java/jdk1.7.0_67/bin:/opt/java/jdk1.7.0_67/jre/bin
If You are not using jre or do not want to set jre path use only # export PATH=$PATH:/opt/java/jdk1.7.0_67/bin
The first part $PATH ensures rest of the system paths remains unchanged.
Optional
To set Java Environmental Variable # export JAVA_HOME=/opt/java/jdk1.7.0_67/ # export JRE_HOME=/opt/java/jdk1.7.0_67/jre
The current release of Java is Java 8 Update 45 (jdk1.8.0_45). It is recommended to update/install latest Java Version. Here is the link to install Java in Linux, the easiest way : http://www.tecmint.com/install-java-jdk-jre-in-linux/