Java has issues both with latency and memory usage due to the garbage collector and general age of the language (missing modern features like value types). Per

Java has issues both with latency and memory usage due to the garbage collector and general age of the language (missing modern features like value types). Performance is.. complex. The lack of value types causes a lot more indirection, the hotspot compiler patches away some of it, the copy collector will compress connected objects together so that they will fit 'automagically' into CPU cache. Unoptimized Java code may often run faster than unoptimized C/C++ code, but Java gives you only vague, global flags for attempting to tune memory behavior and code generation. For monolithic Java applications, you can have a lot of different memory patterns internally (short term objects for the web stack, medium-term objects for transactional state, plus long-term objects representing accumulated state) which can really muck with the garbage collector's assumptions around generations. For server applications, this can cause things like heavy load causing request/response short-term state to be promoted to the mature generation. You start having to break up monolithic applications for performance reasons. But, that still is being a victim of your success - and you would be better off by default creating the first version of your application in a language that allows your developers to iterate quickly.