Foo.java

public class Foo {
  private static final int ITERATIONS = 10000000;
  public static void main(String[] args) {
    Foo foo = new Foo();
    int i = Integer.parseInt(args[0]);

    System.out.println(i);
    if (args[1].equals("a")) {
      System.out.println("a");
      for (int z = ITERATIONS; z > 0; z--) {
        foo.a(i);
      }
    } else {
      System.out.println("b");
      for (int z = ITERATIONS; z > 0; z--) {
        foo.b(i);
      }
    }
  }

  public Foo() { }

  public void a(int count) {
    while (count > 0) {
      count -= 1;
    }
  }

  public void b(int count) {
    do {
      count -= 1;
    } while (count > 0);
  }
}

perf stat.txt

⓿ wopr(~)
% perf stat java Foo 1 a |& grep -v 'not supported'
1
a

 Performance counter stats for 'java Foo 1 a':

        117.422078      task-clock (msec)         #    1.183 CPUs utilized
               201      context-switches          #    0.002 M/sec
                42      cpu-migrations            #    0.358 K/sec
             2,792      page-faults               #    0.024 M/sec
       191,820,684      cycles                    #    1.634 GHz
       212,036,834      instructions              #    1.11  insns per cycle
        39,703,674      branches                  #  338.128 M/sec
         1,367,419      branch-misses             #    3.44% of all branches

       0.099271927 seconds time elapsed

⓿ wopr(~)
% perf stat java Foo 1 b |& grep -v 'not supported'
1
b

 Performance counter stats for 'java Foo 1 b':

        121.188996      task-clock (msec)         #    1.159 CPUs utilized
               198      context-switches          #    0.002 M/sec
                47      cpu-migrations            #    0.388 K/sec
             2,502      page-faults               #    0.021 M/sec
       189,602,621      cycles                    #    1.565 GHz
       209,196,956      instructions              #    1.10  insns per cycle
        39,064,414      branches                  #  322.343 M/sec
         1,352,431      branch-misses             #    3.46% of all branches

       0.104585771 seconds time elapsed