Java is an absolutely huge programming language. It is most commonly encountered by surfers on the web in the form of applets, which are mini-programs to provide interactivity. Applets are strictly governed by security protocol so they can't be used like viruses. Servlets are mini Java programs that reside on web server computers. Java is also capable of full-sized, fully functional programs, or applications. Some web servers are Java-powered. Java caters for databases, games, file transferring... just about anything. You need an IDE to program in it, and a JRE to have Java run on your computer. Java is PARTIALLY compiled into byte code, so any computer ( PC, Mac, etc) with a JRE can run the same program. It is an object-oriented language. It is free to download from Sun.
Hope it helps.
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