Add Sun/Oracle java as an alternative

update-alternatives.sh

#!/bin/bash

# something in PATH env to lookup name in
LINK_PATH=/usr/bin

# where jdk is install to?
JDK_INSTALL_PATH=/opt/jdk1.7.0_21/bin

# alternative prefix
ALTER_PREFIX=oracle

ARGS=
OPT="--install"

for x in java javac keytool jstack jar jmap jhat; do
        ARGS="$ARGS $OPT $LINK_PATH/$x $ALTER_PREFIX-$x $JDK_INSTALL_PATH/$x"
        if [[ $x == "java" ]]; then
                ARGS="$ARGS 1"
                OPT="--slave"
        fi
done

update-alternatives $ARGS

# update-alternatives --install /usr/bin/java oracle-java /opt/jdk1.7.0_21/bin/java 1 --slave /usr/bin/keytool oracle-keytool /opt/jdk1.7.0_21 /bin/keytool --slave
/usr/bin/javac oracle-javac /opt/jdk1.7.0_21/bin/javac --slave /usr/bin/jar oracle-jar /opt/jdk1.7.0_21/bin/jar --slave /usr/bin/jmap oracle-jmap /opt/jdk1.7.0_21/bin/jmap --slave /usr/bin/jstack oracle-jstack /opt/jdk1.7.0_21/bin/jstack