@worldsendless It's much faster than any of these options, though how much depends on what you're doing, with PHP and JS often coming close.
It has so much more good code written for it than anything else. Python comes close, but it's the slowest and has the least support for multi-threaded computing (due to the GIL).
For webdev specifically, the JVM doesn't have the very best web frameworks. The currently popular ones are Spring MVC and Play. These are both serviceable frameworks.
@worldsendless Where the JVM really shines in webdev is when you have a lot of JVM-related backend code already (or if you want to use JVM-related technologies).
Then you can just natively use your JVM code and the webdev code is just a thin layer on top of your JVM ecosystem.
Note that you'll still realistically need JS along with the JVM, but it can be relatively simple front-end code (and/or leveraging JS frameworks), with the JVM language(s) doing the heavy lifting.
@urusan Excellent point, sharing with the other non-webdev business logic things. Come to think of it, I have used some of that (ie Mallet for text processing).
About the speed vs Python, though -- isn't that mostly a myth? Very rarely is python itself doing anything heavy. It just wraps the C code, right?
@worldsendless Yes, but it's only relevant for matrix calculations or problems you can reframe in a matrix form.
So it's great for deep learning and scientific computing, but not so much for web development.