Perhaps the problems are with the way the Java program is written and run? Back in 2012: "5) The idea is to help you understand that you aren't comparing what

Perhaps the problems are with the way the Java program is written and run? Back in 2012: "5) The idea is to help you understand that you aren't comparing what you say you're comparing. If your intention is to compare time taken to grow a list, then shouldn't you start with lists that are the same size, and start with program heap that's the same size, and use the same max heap size? user+sys for your Java program = 20.56s But change ArrayList<Integer> s = new ArrayList<Integer>(); to ArrayList<Integer> s = new ArrayList<Integer>(8192); and run with java -Xms1G PrimeNumbersBenchmarkApp user+sys = 6.9s I don't think you're comparing what you say you're comparing." http://www.famzah.net/download/langs-performance/java-discussion-by-Isaac-Gouy/ http://www.famzah.net/download/langs-performance/java-discus...