In this tutorial we aim to illustrate the "Do's and Don't's" of writing a micro-benchmark in Java.  Especially JVMs with HotSpot technology, which are the norm these days, offer countless opportunities for making fatal mistakes.  Just to name a typical one:  often the code segment whose performance is supposed to be measured falls victim of the so-called "dead code elimination", which means: the compiler optimizes it away.  Hence, what is measured is the performance of "nothing".  The affected micro-benchmark will still yield a result, but it is meaningless.

In the tutorial we discuss this and several other mistakes, using a case study for illustration and derive guidelines for successful micro-benchmarking in Java. In a workshop setting with opportunity for hands-on labs the attendants will have a chance to implement a micro-benchmark themselves, thereby exploring the intricacies of performance measurement in Java.  We will also review a given micro-benchmark, scrutinize and improve it until it yields meaningful results.