Java does not have primitives for unsigned integers.

Comparisons of unsigned quantities can be achieved by adding
MIN_VALUE to both sides of a signed inequality.  For example:

public class ULong {
    private long value;
    public boolean gt(long ulong) {
        return value + Long.MIN_VALUE > ulong + Long.MIN_VALUE;
    }
}

When the machine architecture supports unsigned comparisions, as is
the case for SPARC, the compiler can recognize this idiom and utilize
the unsigned comparison instructions.

Note that the use of + in the method gt() above can correctly be replaced
with either - or ^.  (The desired effect is the flipping of the sign bit.)