Configuring JDTLS

[sabinpocris]

Hi,
If I am into a Maven project, I get "file is a non-project file, only syntax errors are reported" .

However, if i change the -data parameter I get "class cannot be resolved to a type", even though the class's implementation is in the same folder.

Googling I saw another issue like this, maybe using (java-mode . ("jdtls" "-data" ".jdtls-cache")) is not the right choice?

What can I do?

I'm using the last jdtls snapshot, last eglot version and openjdk 18.

[narendraj9]

Here is what works for me:

(defun java-eclipse-jdt-launcher (_arg)
  "Returns a command to start Eclipse JDT launcher script `jdtls'."
  (let ((launcher-script (expand-file-name "org.eclipse.jdt.ls.product/target/repository/bin/jdtls" "~/code/eclipse.jdt.ls/"))
        (root-directory (project-root (project-current))))
    (if (file-exists-p launcher-script)
        (list launcher-script
              "-data"
              (expand-file-name (format "%s-%s" (md5 root-directory)
                                        (file-name-base (directory-file-name root-directory )))
                                "~/code/jdt-workspace/"))
      (message "Failed to find any JDT jar files.")
      nil)))

(add-to-list 'eglot-server-programs `(java-mode . ,#'java-eclipse-jdt-launcher))

I use a separate directory for each project as the jdtls data directory for the project. ^

You should change "~/code/jdt-workspace/" to a directory that you would like to use as the workspace directory and it should be outside all of the projects that you plan to use jdtls for.