How to install Java 7 in Ubuntu 12.04/12.10

Java is a object-oriented language developed by Sun Microsystems in the early 1990. Java is a general-purpose, concurrent, class-based, object-oriented language that is specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be