Installing JAVA 7 (JDK 7u75) on a Linux machine

Installing java on a linux machine is very simple but you can mess it up, if not done properly.

Follow the steps below:

Step 1: Download the tar.gz packages using the below links:
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64 bit
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cd /opt/
# wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u75-b13/jdk-7u75-linux-x64.tar.gz"
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32 bit
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# cd /opt/
# wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u75-b13/jdk-7u75-linux-i586.tar.gz"
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Step 2: Unpack the jdk pacjages using the below command:
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tar -xzf jdk-7u75-linux-x64.tar.gz
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Step 3: Install Java with Alternatives
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Now, we need to set up the newer version of Java using alternatives. Run the below commands:

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#cd /opt/jdk1.7.0_75/
#alternatives --install /usr/bin/java java /opt/jdk1.7.0_75/bin/java 2
#alternatives --config java
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On running the command "alternatives --config java", you will receive the following output. Select the option  "3" to get the desired path.

Step 4: Now you may also required to set up javac and jar commands path using alternatives command.
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# alternatives --install /usr/bin/jar jar /opt/jdk1.7.0_75/bin/jar 2
# alternatives --install /usr/bin/javac javac /opt/jdk1.7.0_75/bin/javac 2
# alternatives --set jar /opt/jdk1.7.0_75/bin/jar
# alternatives --set javac /opt/jdk1.7.0_75/bin/javac
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Step 5: Most of the java applications will work only if environment variables are set. For that, add the following variables to ~/.bashrc .

Just vi the file "~/.bashrc " and add entries as below:

Setup JAVA_HOME Variable
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export JAVA_HOME=/opt/jdk1.7.0_75
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Setup JRE_HOME Variable
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export JRE_HOME=/opt/jdk1.7.0_75/jre
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Setup PATH Variable
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export PATH=$PATH:/opt/jdk1.7.0_75/bin:/opt/jdk1.7.0_75/jre/bin
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Now, you are done. Just check the java version as below:

Done :)