java: Compile with -Xlink:unchecked
java: Fix unchecked warning from compiler
java: Silence annoying ant warning

See [1] for more details.

  [1] http://stackoverflow.com/a/5103432/28804
java: Retrieve one byte of input from stdin

Implements the ',' operation.
java: Map Brainfuck operations as closures (anonymous inner classes)

A bit more elegant than having a long list of methods in the class,
although maybe a bit uglier and less organized, but it also feels
more Java-like than relying on reflection.