rust - Could Java be made to run without a GC

Question

I can't find much online on this but here is my thought, a language like rust analyses on compile when to free objects from memory. Why can't the same be done with Java then we don't need a garbage collector. Unless it's because this would make the coding even more complicated.

So the question being could the Java compiler manage memory before runtime

question from:https://stackoverflow.com/questions/65940510/could-java-be-made-to-run-without-a-gc

Answer 1

Java can do "simple" cleanups, where it knows for sure that an object didn't leak from the stack and thus is safe to clean up when the stack is cleaned up. Such escape analysis is also used in other ways, for example to determine whether the lock needs to be taken when you enter a synchronized block: if the reference is guaranteed to be stack-confined, you don't need to take the lock because there is no risk of any other thread seeing it.

The difference between Java and Rust is that Rust has a strict notion of ownership, so it is possible to know statically when all objects can be cleaned up safely; Java doesn't have this notion, so it has to, in general, rely on the GC to work it out.

So, essentially, no, Java can't do without a GC, because that is how the language was designed; Rust can do without a GC because that is how that language was designed.