Java is an easy to learn,object-oriented programming language developed by Sun Microsystems.

There are many different programming languages and Java is another one but it is unique. Say for example you write a Visual Basic program and run  your application. It executes correctly on Microsoft Windows but you take your application to Apple Mac OS and it will not run at all. With Java you can write an application and it can run one many different operating systems (including Windows,Mac OS,Unix and Mainframes) without modification to the code.

Typically when developing an application in a programming language,the source code is passed through a compiler (another application) that transforms the code into a set of native instructions (for target operating system). For example,when developing applications that run on Windows Operating Systems,they usually run on Intel processors (like Pentium chipset). The compiler converts the source code into instructions that the processor can understand and execute.

When writing Java applications,the developer does not need to directly call Windows (or other operating systems) library functions. The Java compiler does not write native instructions,instead it generates byte-codes for a virtual machine called Java Virtual Machine (JVM).