Java LSP backends are basically headless Eclipse and NetBeans, they definitely go beyond syntactical errors. There's also the upcoming Metals v2 that's using a

Java LSP backends are basically headless Eclipse and NetBeans, they definitely go beyond syntactical errors. There's also the upcoming Metals v2 that's using another compiler frontend optimized for performance, Google Turbine: https://metals-lsp.org https://metals-lsp.org Actionable diagnostics for Java aren't implemented yet though.