Why Do I Need Java Software?

Java is a programming language and platform for creating and running computer programs. It was primarily built under the sponsorship of a company named Sun Microsystems with the goal of making it as easy and reliable as possible to create programs that run on as many different devices and operating systems as possible.

Writing Java Programs

If you are a developer who wishes to create programs using the Java programming language, then you will need a copy of both the Java Runtime Environment and the Java Development Kit on your computer in order to work. This is true even if you wish to develop Java programs designed to run within a web browser, called Applets.

Your Program Requires It

The simplest reason why you would need Java on your computer is because a program you have downloaded and wish to use requires the Java Runtime Environment in order to function. These programs were written by developers who choose Java as their language because of its ability to create code that can run on as wide a variety of devices as possible, from cell phones to personal computers, without modifications. If your program requires Java to be present, it will inform you with an error message when you try to run it.

Reasons for the Requirement

In order to run on a diverse set of computers, Java programs cannot be written specifically for any one of the computers they will run on. Even if a Java programmer could write his program for a specific computer, it may break as soon as a new model is released that supports different features, and it may never support completely new and unforeseen devices, like smart phones. Instead, Java programs are written for an imaginary computer called the Java Virtual Machine.

The Java Virtual Machine

Then, a special program that is part of the Java installation on each user's computer contains instructions for how to translate commands for the Java Virtual Machine into commands for their own computer. So long as the user's computer has the tools to understand Java Virtual Machine commands, and so long as the Java programmer creates code correctly for the Java Virtual Machine, programs will work, regardless of the computer.

Disadvantages

The disadvantage of this method is, unlike with Windows EXE files, Mac OS X APP bundles and Linux applications, Java programs require something extra be installed on each user's computer; a program that can translate Java Virtual Machine code into code for the native computer. This is the Java Runtime.

References

• Sun Microsystems: About Java Technology