There are hundreds of warnings in LSP4J in my workspace warnings.txt - this is with Eclipse Version: 2025-09 (4.37.0) and build settings as set in Eclipse with this bit of gradle.

Some of these warnings are not that helpful, so can probably be turned off (such as The value of the parameter params is not used) and a lot of them are related to resource leaks, so those could be fixed with appropriate suppress warnings as most of them are the result of calling methods that are annotated @CanIgnoreReturnValue (can Eclipse support error-prone annotations?).