{
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  inputs.systems.url = "github:nix-systems/default";

  outputs = { self, systems, nixpkgs }:
    let
      eachSystem = nixpkgs.lib.genAttrs (import systems);
    in
    {
      devShells = eachSystem (system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in {
          default = nixpkgs.legacyPackages.${system}.mkShell {
            buildInputs = [
              pkgs.jdk21
              (pkgs.maven.override {
                jdk = pkgs.jdk21;
              })
              pkgs.expect
              pkgs.zip
            ];
          };
      });
    };
}