Apart from big differences between Java and Rust like memory management (not just GC vs. lifetimes but also stack allocation), approach to threading, and Cargo vs. Maven, Rust is so much nicer in the seemingly little things like:
* UTF-8 everywhere instead of UTF-16 everywhere.
* Unsigned integers.
* Bytes from I/O being unsigned by convention.
* Ability to bake plain old data into the data segment of the executable with genuinely no run-time initialization.