Snippet to configure JDT-LS for use with tools like Lombok

set-up-jdtls.el

(after! lsp-java
  (setq! lsp-java-vmargs
         ;; Provide access to internals for compiler related tooling (such as
         ;; LSP introspective servers or annotation preprocessors - like
         ;; Lombok).
         (apply #'append lsp-java-vmargs (mapcar (lambda (pkg) (list "--add-exports"
                                                                (format "%s=ALL-UNNAMED" pkg)))
                                                 '("jdk.compiler/com.sun.tools.javac.code"
                                                   "jdk.compiler/com.sun.tools.javac.util"
                                                   "jdk.compiler/com.sun.tools.javac.api"
                                                   "jdk.compiler/com.sun.tools.javac.tree"
                                                   "jdk.compiler/com.sun.tools.javac.resources"
                                                   "java.management/sun.management"))))

  (add-hook! java-mode
    (when-let ((lombok-jar (getenv "LOMBOK_JAR")))
      (when (file-exists-p lombok-jar)
        (message "adding Lombok to JVM classpath (%s)" lombok-jar)
        (setq-local lsp-java-vmargs
                    (append (list (format "-Xbootclasspath/a:%s" lombok-jar)
                                  (format "-javaagent:%s" lombok-jar))
                            lsp-java-vmargs)))))