This is the chart comparing the java.util.logging mechanism with plain simple System.out.println to log messages in a Java program.

In each test, N (1, 5 and 10) threads were launched. Each thread produces 100000 log messages in a loop and records the total time. The output of the program was redirected to a file (both standard output and standard error).

The chart shows the average time each thread took to log the 100000 messages.

The thing to note is that java.util.logging scales a lot worse than plain System.out.println calls. And things get worse if you're using a FileHandler on the Logger...

This might not be a problem in normal programs, but in my simulation case, it was since I was launching several instances on the same machine.  At some point, logging was a bottleneck...