JVM is impressive until closures are involved, in which case when inlining is not done (either because it cannot be or ever-changing heuristics are not met), yo

JVM is impressive until closures are involved, in which case when inlining is not done (either because it cannot be or ever-changing heuristics are not met), you can drop back to virtual calls and performance suffers a great deal. Compare to C++ where closures can be used with virtually no penalty and aggressively optimized. Even C with its trick of passing an extra *void for environment comes out shining performance-wise in comparison. Edit: There's a good discussion of the problems that JVMs have in this area at http://www.azulsystems.com/blog/cliff/2011-04-04-fixing-the-inlining-problem http://www.azulsystems.com/blog/cliff/2011-04-04-fixing-the-.... "The Problem is a hard one to solve; (i.e. it’s not the case that we’ll wave our wands and do a quick fix & rebuild HotSpot and the problem will go away). John Rose, Doug Lea and I all agree that it’s a Major Problem facing JVMs with long and far reaching implications." Maybe progress will be made soon though, with more pressure caused by increasing use of closures in the new streams library and with anonymous function syntax available now.