RHEL includes the alternatives command providing the ability to point your users to different versions of software while not changing their links to the command. For example if you wanted a specific version of JAVA this can be done with PATH changes or alternatives
for exact info.
/usr/sbin/alternatives --install /usr/bin/java java /location_to_new_java /usr/sbin/alternatives --config java
Repeat for javac
Finally, set the environment for everyone on the machine by creating a java.sh script in /etc/profile.d:
#!/bin/sh export JAVA_HOME=/usr/java/jdk export JRE_HOME=$JAVA_HOME/jre export J2RE_HOME=$JAVA_HOME/jre export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$J2RE_HOME/bin:$PATH