Java Installation step by step in Linux and Ubuntu

Java 1.7 Installation                         

Download Java Package HERE

• Create a Directory

root@rahul-desktop~]#mkdir -p /usr/java

• Extract JDK.tar file to the Directory

root@rahul-desktop~]#tar -xvf jdk-7u11-linux-i586.tar.gz -C /var/java

• Now delete the old java and update new

root@rahul-desktop~]#cd /etc/alternatives/

root@rahul-desktop alternatives]# rm -f java javac keytool

root@rahul-desktop alternatives]# ln -s /usr/java/jdk1.7.0_11/bin/java .

root@rahul-desktopalternatives]# ln -s /usr/java/jdk1.7.0_11/bin/javac .

root@lrahul-desktop alternatives]# ln -s /usr/java/jdk1.7.0_11/bin/keytool .

• Set the class path

root@rahul-desktop~]# vi .bash_profile or .bashrc

export PATH=$PATH:/usr/java/jdk1.7.0_11/bin/
export CLASS=$CLASSPATH:/usr/java/jdk1.7.0_11/jre/lib
:wq!

• Now Verify 

root@rahul-desktop~]#source .bashrc

root@rahul-desktop~]#echo $JAVA_HOME

/usr/java/jdk1.7.0_11

root@rahul-desktop~]#java -version

java version "1.7.0_11"
Java(TM) SE Runtime Environment (build 1.7.0_11-b21)
Java HotSpot(TM) Client VM (build 23.6-b04, mixed mode)