remove java implementation, was merely a book copy

flake.nix

@@ -0,0 +1,38 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    fenix.url = "github:nix-community/fenix";
+  };
+
+  outputs =
+    {
+      nixpkgs,
+      fenix,
+      flake-utils,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        fx = fenix.packages.${system};
+        rust = fx.combine [
+          (fx.fromToolchainFile {
+            file = ./rust-toolchain.toml;
+            sha256 = "sha256-AJ6LX/Q/Er9kS15bn9iflkUwcgYqRQxiOIL2ToVAXaU=";
+          })
+        ];
+        buildInputs = [
+          rust
+          pkgs.cargo-deny
+          pkgs.rust-analyzer
+        ];
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = buildInputs;
+        };
+      }
+    );
+}