Java might be fast once it's had time to warm up, but its startup time is impressive only in how excruciatingly slow it is. I wrote a small utility program in

Java might be fast once it's had time to warm up, but its startup time is impressive only in how excruciatingly slow it is. I wrote a small utility program in Java recently. It was getting slower and slower as it grew, so I profiled it. It turned out the slow parts were every part - the first time that part executes. E.g. parsing the command line arguments was slow the first time, but fast if I did it a second time. Same for reading configuration files, opening sockets, etc. I assume this has to do with a combination of lazy class loading (which is slow) and the JIT compiler not being warmed up. Unfortunately for Java (and its users), you rarely need to parse your arguments a second time, so you never get to experience the case where Java is fast. It needs to be fast the first time, and it's not.