"Java" being used as slang for "coffee"
Java does not have any full form, but a programming language originally developed by James Gosling at Sun Microsystems in 1995. It derives much of its syntax from the most popular programming languages of all time : C and C++. Today Java of Sun Microsystems is a subsidiary of Oracle Corporation.
Java was basically designed to overcome the drawbacks of C++ i.e. to make single application run on multiple platforms like Windows, UNIX & Macintosh, and to make application run on Internet Browsers.
How "Java" got its name
The developers of Java were drinking coffee while they were deciding the name of their programming language. So, they gave it the name "Java" as a slang of "Coffee".