An object-oriented language originally developed at Sun by James Gosling (and known by the name “Oak”) with the intention of being the successor to C++ (the project was however originally sold to Sun as an embedded language for use in set-top boxes). After the great Internet explosion of 1993-1994, Java was hacked into a byte-interpreted language and became the focus of a relentless hype campaign by Sun, which touted it as the new language of choice for distributed applications.
Java is indeed a stronger and cleaner design than C++ and has been embraced by many in the hacker community — but it has been a considerable source of frustration to many others, for reasons ranging from uneven support on different Web browser platforms, performance issues, and some notorious deficiencies in some of the standard toolkits (AWT in particular). Microsoft's determined attempts to corrupt the language (which it rightly sees as a threat to its OS monopoly) have not helped. As of 2003, these issues are still in the process of being resolved.
Despite many attractive features and a good design, it is difficult to find people willing to praise Java who have tried to implement a complex, real-world system with it (but to be fair it is early days yet, and no other language has ever been forced to spend its childhood under the limelight the way Java has). On the other hand, Java has already been a big win in academic circles, where it has taken the place of Pascal as the preferred tool for teaching the basics of good programming to the next generation of hackers.