I'm surprised to find this comment at the bottom of the comment section. My advice, like yours, is to profile performance issues before getting into the hypothe

I'm surprised to find this comment at the bottom of the comment section. My advice, like yours, is to profile performance issues before getting into the hypothesis-change-measure loop. Like you said, it quickly bifurcates the problem space into application code and the JVM and eliminates entire classes of performance problems. It's important to point out too that while most people assume cpu profiling, the JVM and hence most profiling tools also have memory profiling which can be helpful in diagnosing problems (especially ones related to GC). I hope the querent ends up profiling and shares the results. It would be both fun and productive to investigate the results collaboratively.