Can anyone quantify performance differences between C++ and Java?

Question

Java was initially slow before the JIT but today performance is pretty close to C++. I want to know if someone has done measurable performance comparisons between the two langu

Answer 1

In many ways this is like comparing apples to oranges.

C++ is built on the notion that you don't pay a cost for anything you don't use. If you manage memory yourself, if you don't use virtual functions, etc.

Java doesn't give you that freedom. It gives you features that you may not even want. For all you may want to allocate memory yourself, you will have to use heap objects for everything, so you will take a garbage collection impact.

Once you start talking about GUIs, it's an even more difficult comparison since different UI frameworks and toolkits have different performance issues. For example, Swing/AWT will typically be slower than something written directly for the native OS. In C++, you will rarely find a truly portable toolkit, etc.

I think that when developers started openoffice, Java was much slower and the UI toolkits were slow and ugly. Tools like Eclipse prove that you can build relatively nice UIs even in Java, though admittedly, SWT is a toolkit that does a lot of things at the native level.