Introduction to Java

• What is java?...  

                   Java is a programming language that evolved from a language named Oak. Oak was developed by Sun Microsystems in nineties as a platform independent  language aimed at allowing entertainment appliances such as video console and VCR's to communicate. It was originally
developed by "James Gosling" at Sun Microsystems and released in 1995 as a core component of Sun Microsystems Java platform.

James Gosling

                    The very first and most popular reason for learning java is that, it is platform independent. Now how Java is platform independent?. Since on every machine where java is installed creates an environment of it's own i.e creates a virtual machine on top of the underlying operating system. This virtual machine is called as JVM(Java Virtual Machine

                    

                    In java there is a JIT(Just In Time) compiler converts byte code to native machine code.

Hence a java program compiled on one machine can be executed on any another machine having java environment. So java is platform independent.

• What is Byte Code in Java?

                   Byte code is the compiled form of java programs. Once java program is converted into byte code it can transferred over the network and can be executed on any another by Java Virtual Machine. Byte code files normally have a .class extension.

Java Working Diagram.

          

                      In this diagram it is clearly shown about the working of java. First a user understandable code is converted into byte code and then machine understandable code and finally it gets executed. Java can also be called as run time programming language.