Installing JDK, JRE in Ubuntu

Installation of "default-jdk" using "apt-get" was perfect though in my system it was showing that OpenJdk 6 was installed. I did not wanted it and deleted it from Software Manager. Unfortunately, uninstalling OpenJdk 6 installs OpenJdk 7!!!
I was searching for a solution on the web. Then I found the following link. It describes how to install Oracle Jre and Jdk. This link is so helpful.

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http://www.wikihow.com/Install-Oracle-Java-JDK-on-Ubuntu-Linux

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Step Ahead in JAVA

Hello everyone, this is my solution for "Life, the Universe, and Everyting" in SPOJ. It was my first submission in JAVA. Take here a look.

/*
Task: Life, the Universe, and Everything (SPOJ)
Code: TEST
*/

import java.io.*;   // java input\output library 
import java.util.*; // using for Scanner class

class LifeSPOJ {
    public static void main ( String [] args ) {
        Scanner ss = new Scanner(System.in);
        int num;
        num = ss.nextInt(); // nest intejar
        while( num != 42 ) {
            System.out.println( num ); // printing that number
            num = ss.nextInt();
        }
    }
}