gistfile2.txt

$ java HelloWorld
5.316 seconds for 1000000000 iteration: 188111.36192626035 Kcalls/sec
2.866 seconds for 10000000 iteration: 3489.183531053733 Kcalls/sec

HelloWorld.java

class HelloWorld {

    public static void main(String[] args) {
        bench1();
        bench2();
    }
    static void bench1() {
        long repeat = 1000000000L;
        long start = java.lang.System.currentTimeMillis();
        for (long i = 0; i < repeat; i++) {
            Long.toHexString(i);
        }
        long end = java.lang.System.currentTimeMillis();
        double duration = (end - start) / 1000.0; //seconds
        System.out.println(duration + " seconds for " + repeat + " iteration: " + repeat / 1000.0 / duration + " Kcalls/sec");
    }
    static void bench2() {
        long repeat = 10000000L;
        long start = java.lang.System.currentTimeMillis();
        for (long i = 0; i < repeat; i++) {
            String.format("%016X", i);
        }
        long end = java.lang.System.currentTimeMillis();
        double duration = (end - start) / 1000.0; //seconds
        System.out.println(duration + " seconds for " + repeat + " iteration: " + repeat / 1000.0 / duration + " Kcalls/sec");
    }
}