/usr/java/default/

/etc/profile.d/java.sh

export JAVA_HOME=/usr/java/default/

alternatives --install /usr/bin/java java /usr/java/default/bin/java 999999
           --slave /usr/bin/keytool keytool /usr/java/default/bin/keytool
           --slave /usr/bin/rmiregistry rmiregistry /usr/java/default/bin/rmiregistry

alternatives --install /usr/bin/javac javac /usr/java/default/bin/javac 999999
           --slave /usr/bin/jar jar /usr/java/default/bin/jar
           --slave /usr/bin/rmic rmic /usr/java/default/bin/rmic

echo "export JAVA_HOME=/usr/java/default/" > /etc/profile.d/java_home.sh

export JAVA_HOME=/usr/java/jdk1.3

export PATH=$PATH:/usr/java/jdk1.3/bin

export CATALINA_HOME=/path/to/tomcat

[root@host ~]# echo $JAVA_HOME
/usr/java/j2sdk1.4.2_09

[user@base ~]$ locate bin/java
/usr/bin/java
/usr/bin/javac
/usr/bin/javadoc
/usr/bin/javaws
/usr/java/jdk1.6.0_31/bin/java
/usr/java/jdk1.6.0_31/bin/javac
/usr/java/jdk1.6.0_31/bin/javadoc
/usr/java/jdk1.6.0_31/bin/javah
/usr/java/jdk1.6.0_31/bin/javap
/usr/java/jdk1.6.0_31/bin/javaws
/usr/java/jdk1.6.0_31/jre/bin/java
/usr/java/jdk1.6.0_31/jre/bin/java_vm
/usr/java/jdk1.6.0_31/jre/bin/javaws