Well, even in Java 8, long and int are still signed, only some methods treat them as if they were unsigned. If you want to write unsigned long literal like that, you can do
static long values = Long.parseUnsignedLong("18446744073709551615");
public static void main(String[] args) {
System.out.println(values); // -1
System.out.println(Long.toUnsignedString(values)); // 18446744073709551615
}