How can I do a meaningful java code benchmark with reflection? [duplicate]

This question already has an answer here:

• How do I write a correct micro-benchmark in Java? 11 answers

How can I benchmark java reflection methods properly? When I run this the results are very random and inconsistent with the methods Im running it on.

long start = System.currentTimeMillis();
for (int j = 0; j < 1000000; j++) {
    method.invoke(instance, null);
}
System.out.println(System.currentTimeMillis() - start);