Notch's Ludum Dare 22 entry.
Conway's Game of Life Java applet
Ludum Dare 46 entry
Physics engine liquid in Java.
Asteroids-like space shooter written in Java 2D
Notch's Prelude of the Chambered 48-hour game
Sudoku Java applet
Animated maze generator and solver in Java
Ludum Dare game entry from the 10th Anniversary Ludum Dare! Theme "Tiny World". Written in Java, ...