Install JAVA.1.7 in linux

To Install JAVA.1.7 in Linux

#wget http://download.oracle.com/otn-pub/java/jdk/7/jdk-7-linux-i586.tar.gz

#tar -xzf jdk-7-linux-i586.tar.gz

#mv ./jdk1.7.0/ /usr/lib/jvm/jdk1.7.0

#update-alternatives --config java
In case you have other answer from update-alternatives --config java command, e.g. ‘no alternatives for java’, try this command:

#update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7.0/jre/bin/java 0

To know under what number you will config you new Java installation.Remember the last number and press enter to exit this utility.

#update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7.0/jre/bin/java 3 

#java -version
java version “1.7.0″
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) 64-Bit Server VM (build 21.0-b17, mixed mode)

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To update javac
#javac -version
  javac 1.6.0_26 

# update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.7.0/bin/javac 3
# update-alternatives --config javac
#  javac -version