I stopped reading here because this quote makes it clear the author has no idea what they are talking about. In the Benchmark game, Python beats Java in only one benchmark and loses badly in the others. In general, Python is MUCH slower than Java. For the n-body simulation the difference is almost a factor of 100x. (https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/python3-java.html)