alt Hacker News> No, you really can. You can use GC crates and the performance will be like Java
It won't be anywhere near Java's. Those GCs are mark-and-sweep collectors. Java uses moving collectors. Moving collectors are used to avoid the high overheads of malloc/free in the C runtime (or of any free-list-based mechanism). They're a performance optimisation. Heap allocations in Java behave more like arenas than like heap allocations in languages with non-moving memory management, whether it's C, Rust, Python, or Go. Other runtimes that use moving collectors are Google's V8 and Microsoft's .NET, except that Java's ZGC has no GC pauses.
I'm well aware. I don't know a moving GC crate for Rust, but I do know that building a safe moving GC crate for Rust is possible, using the same principles as existing GC crates. It will not be exactly as performant as Java, because you don't have compiler support for updating pointers, but it will almost be - pointers inside the data structures can be updated via derive, the only pointer that cannot is the pointer to the data structure itself, so you will need to heap-allocate the data structure (the GC root). Given that in Java everything is under indirection anyway, this will have the same efficiency or even better.