Java

.java files follow the same model: a local analysis with tree-sitter as soon as a file opens, then jdtls (Eclipse JDT Language Server) for everything else.

Without a server

• Syntax errors.
• File structure (Ctrl+F12): classes, interfaces, enums, records, methods, constructors and fields.
• Occurrences, and the declaration in the file.
• Completion of names, keywords, common types, and templates: psvm, sout, fori, iter, ifn, try, test…

With jdtls

Member completion, tooltips, compiler errors, navigation in the project and its Maven or Gradle dependencies, rename, quick actions, Reformat code and Optimize imports.

Install it from Search Everywhere (Java: Install Language Server) in ~/.atelier/lsp/jdtls. It starts with Java 21 or newer (JAVA_HOME, otherwise the PATH); a jdtls on the PATH works too. Each project has its own jdtls workspace in ~/.atelier/lsp/jdtls-data.

Running

Shift+F10 runs the active file with java path/to/Main.java (a JDK with source mode, Java 11+). For a whole project, see Maven & Gradle.