sun java Linux install in openSUSE using update-alternatives

#!/bin/bash
#
# Instructions:
#   Download the sun/oracle java .tar.gz package.
#   Extract the .tar.gz in  your /opt/ directory.
#   In this script, edit XSUNJAVA= to point to the new directory in /opt
#   run this script
#   If it doesn't work, try to find out which variable is wrong (libDir, XOPENJDK, XSUNJAVA), and try again.

# generic, extracted tarball:
export XSUNJAVA=/opt/jdk1.7.0_04/
# rpm install:
# export XSUNJAVA=/usr/java/jdk1.7.0_04

# Depending on if you have a 64 bit or 32 bit machine
if [ -e /usr/lib64 ]; then
    libDir=/usr/lib64
else
    libDir=/usr/lib
fi

# opensuse 12.1:
export XOPENJDK="${libDir}/jvm/java-1.6.0-openjdk/"
# opensuse 12.1 2012-07-04
if [ ! -e $XOPENJDK ]; then
    export XOPENJDK="${libDir}/jvm/java-1.6.0-openjdk-1.6.0/"
fi

# ubuntu 12:
# export XOPENJDK=/usr/lib/jvm/java-6-openjdk-amd64/

update-alternatives --remove-all java
update-alternatives --remove-all javac
update-alternatives --remove-all keytool
update-alternatives --remove-all javaplugin
update-alternatives --remove-all javaws

# Directories (for use in JAVA_HOME environment variable)
update-alternatives --install /opt/java java_home ${XSUNJAVA} 1
update-alternatives --install /opt/jdk  jdk_home  ${XSUNJAVA} 1
update-alternatives --install /opt/java java_home ${XOPENJDK} 2
update-alternatives --install /opt/jdk  jdk_home  ${XOPENJDK} 2
update-alternatives --set java_home ${XSUNJAVA}
update-alternatives --set jdk_home ${XSUNJAVA}

# Commands using alternative directories
update-alternatives --install /usr/bin/java java /etc/alternatives/jdk_home/bin/java 1
update-alternatives --install /usr/bin/javac javac /etc/alternatives/jdk_home/bin/javac 1
update-alternatives --install /usr/bin/keytool keytool /etc/alternatives/jdk_home/bin/keytool 1
update-alternatives --install /usr/bin/javaws javaws /etc/alternatives/jdk_home/bin/javaws 1
update-alternatives --set java /etc/alternatives/jdk_home/bin/java
update-alternatives --set javac /etc/alternatives/jdk_home/bin/javac
update-alternatives --set keytool /etc/alternatives/jdk_home/bin/keytool
update-alternatives --set javaws /etc/alternatives/jdk_home/bin/javaws

# For the browser plugin
update-alternatives --install ${libDir}/browser-plugins/libnpjp2.so javaplugin /etc/alternatives/java_home/jre/lib/amd64/libnpjp2.so 1
update-alternatives --install ${libDir}/browser-plugins/libnpjp2.so javaplugin ${libDir}/IcedTeaPlugin.so 2
update-alternatives --set javaplugin /etc/alternatives/java_home/jre/lib/amd64/libnpjp2.so

# add JAVA_HOME to current shell
export JAVA_HOME=/etc/alternatives/java_home/

# add JAVA_HOME to your environment
if ! egrep -c "^JAVA_HOME=/etc/alternatives/java_home/$" /etc/profile >/dev/null 2>&1; then
    # ^ if the exact line we want is not in /etc/profile
    echo "Updating /etc/profile"
    # remove any JAVA_HOMEs in there
    egrep -v "^JAVA_HOME" /etc/profile > /etc/profile.javatmp
    # add JAVA_HOME
    echo "JAVA_HOME=$JAVA_HOME" >> /etc/profile.javatmp
    mv /etc/profile.javatmp /etc/profile
    echo "Done updating /etc/profile"
fi