selecting jdk and changing java_home

add.bashrc

# finds and export JAVA_HOME
#export JAVA_HOME=$(dirname $(dirname $(readlink -e /usr/bin/javac)))
export JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:/bin/javac::")

jdk

#!/bin/bash
if [ $# -ne 1 ]
then
    echo please provide the jname.
    update-java-alternatives -l
    return;
fi
jname=$1
sudo update-java-alternatives -s $jname
. ~/.bashrc

jdk7

#!/bin/bash
#jdk=$(readlink -f ./jdk)
#echo jdk: $jdk
#. $jdk java-7-oracle
. $(dirname "$BASH_SOURCE")/jdk java-7-oracle

jdk8

#!/bin/bash
#jdk=$(readlink -f ./jdk)
#echo jdk: $jdk
#. $jdk java-8-oracle
. $(dirname "$BASH_SOURCE")/jdk java-8-oracle