dev-templates/java/flake.nix

{
  description = "A Nix-flake-based Java development environment";

  inputs.nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0.1.*.tar.gz";

  outputs = {
    self,
    nixpkgs,
  }: let
    javaVersion = 20; # Change this value to update the whole stack
    overlays = [
      (final: prev: rec {
        jdk = prev."jdk${toString javaVersion}";
        gradle = prev.gradle.override {java = jdk;};
        maven = prev.maven.override {inherit jdk;};
      })
    ];
    supportedSystems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];
    forEachSupportedSystem = f:
      nixpkgs.lib.genAttrs supportedSystems (system:
        f {
          pkgs = import nixpkgs {inherit overlays system;};
        });
  in {
    devShells = forEachSupportedSystem ({pkgs}: {
      default = pkgs.mkShell {
        packages = with pkgs; [gradle jdk maven];
        programs.vscode = {
          extensions = with pkgs.vscode-extensions; [
            mkhl.direnv
            redhat.java
          ];
        };
      };
    });
  };
}