"Write once, run anywhere" is a pipe dream but Java came closer than anyone else by far.

It can help with standardization and some security benefits to run things in the JVM, part of the reason it's so popular in enterprise

There's also Groovy. A data execution pipeline program I use called NextFlow uses Groovy based scripts.

And compiling for different architectures can be very difficult. I've done a lot of work Power9 computers and it's not as simple as having the right compiler flags. Often the dependencies aren't built for your platform either so you have to go and compile those too. It can be quite a hassle.

JIT compiling and byte code morphing and instrumentation. For instance data base persistence is usually done by instrumentation tools, that add instructions to keep track about transactions and modified objects, or new objects that need persisting. And endless more things.