Is Java really slow?

Answer 1

A hammer is much slower at rolling out dough than many other tools. Doesn't make the hammer "slower", nor less useful for the tasks that it is designed to do.

As a general programming language, Java is on par with many (if not most) for a wide array of programming tasks. There are specific, trivial tests for which Java will not outperform hand-coded solutions in less sophisticated languages, ones that are "closer to the metal".

But when it comes to "real world applications", Java often is the Right Tool. Now, that said, nothing will stop developers from making a slow-performing solution using ANY tool. Misuse of tool is a well known problem (just look at PHP's and VB's reputations). However, Java's (mostly) clean design and syntax does do a lot to reduce misuse.