According to the comparison between Java, C++, and C# in the link above, the three languages are all fairly identical when it comes to int and double calculations. Where Java is extremely slow is in Trig calculations. However, using JET 3.5, the speed is faster than C.
I was wondering how exactly JET is faster than the JVM in 1.4.2.03. Does it still use the IEEE 754 standard and calls through the StrictMath class? The review seems to imply that there is lower precision.