Ma scusa esiste la documentazione JAVA....

http://docs.oracle.com/javase/6/docs...lang/Math.html

static double nextAfter(double start, double direction)
Returns the floating-point number adjacent to the first argument in the direction of the second argument.

static float nextAfter(float start, double direction)
Returns the floating-point number adjacent to the first argument in the direction of the second argument.

non è che per qualunque piccola cavolata possiamo darti la pappa in bocca...