It's psychological. Most users don't really care how fast something runs once the JIT warms up: instead, they care about the latency of their starting the progr

It's psychological. Most users don't really care how fast something runs once the JIT warms up: instead, they care about the latency of their starting the program to the time they can use it and use this latency as a psychological measure of the performance of the program as a whole. Stupid? Yes. But that's what actually happens. The JVM has always had a slow startup path. Much slower-overall systems like Python don't. That's why people don't complain about Python performance and do complain about Java performance.