Debugging Java code with nvim-jdtls and nvim-dap

[britter]

Hi,

I'm trying to set up nvim as an IDE replacement for Java development. I'm using the nvim-jdtls plugin to configure pkgs.jdt-language-server and am struggling to get the integration between nvim-jdtls and nvim-dap working.

nvim-dap's documentation states:

You do not have to define dap.adapters.java yourself.

However, when I try to debug an application by calling :DapContinue the status line says

No configuration found for java. You need to add configs to dap.configurations.java (See :h dap-configuration)

My configuration looks like this:

# java.nix
{
  lib,
  pkgs,
  ...
}: let
  singleFile = dir: let
    files = builtins.attrNames (builtins.readDir dir);
  in
    if builtins.length files == 1
    then "${dir}/${(builtins.elemAt files 0)}"
    else throw "Directory ${dir} does not contain exactly one file.";
in {
  programs.nixvim.plugins.nvim-jdtls = {
    enable = true;
    cmd = [
      (lib.getExe pkgs.jdt-language-server)
    ];
    initOptions = {
      bundles = [(singleFile "${pkgs.vscode-extensions.vscjava.vscode-java-debug}/share/vscode/extensions/vscjava.vscode-java-debug/server")];
    };
  };
}

# debug.nix
_: {
  programs.nixvim = {
    plugins.dap = {
      enable = true;
      extensions.dap-ui.enable = true;
    };
    keymaps = [
      {
        action.__raw = "require('dap').toggle_breakpoint";
        key = "<leader>dt";
        mode = ["n"];
      }
      {
        action.__raw = "require('dap').continue";
        key = "<leader>dc";
        mode = ["n"];
      }
      {
        action.__raw = "require('dap').step_over";
        key = "<leader>ds";
        mode = ["n"];
      }
      {
        action.__raw = "require('dap').step_into";
        key = "<leader>di";
        mode = ["n"];
      }
    ];
  };
}

And then another file that include the two and some other configurations.