That sounds like FUD. You can't possible make such a generic statement. Where are you basing this statement ?

FWIW, most python code uses libraries which are written in C/C++. This means that only a small fraction of the actual program runs in python. I hope you're not benchmarking a for loop but a full program instead.

Also, you cannot compare those two languages since java practically does not use any libraries at all. At best it has language extensions but not any libraries that other non-java programs may use. Python on the other hand mostly uses existing platform libraries and wraps them. As such, you cannot compare a gui program written in java and in python since the java version will have a very very bad gui with many limitations. Just try to make a GTK or Qt or Wx or ...(fill the blank)... -based gui in java. Since you cant, you cannot perform realistic speed comparisons.

my 0.02€