Tremendous amounts of the Java out there in the training corpus would be based on outdated patterns, especially anything pre-Java 8 or pre-Java 21 (Pattern Matching, Project Loom). I don’t think this negatively impacts the quality of LLM Java code but it sort of calls into question whether this is simply a case of more is better.

My personal experience is that LLMs are quite good at one-shotting complex solutions in both Rust and Go, and tend to be idiomatic.