adding eclipse java support to neovim

home/programs/nvim.nix

@@ -7,6 +7,11 @@
     vimAlias = true;
     defaultEditor = true;
 
+    extraPackages = with pkgs; [
+      jdtls
+      jdk
+    ];
+
     initLua = ''
       vim.opt.number = true
       vim.opt.relativenumber = true
@@ -85,6 +90,32 @@
           delete = { text = "_" },
         },
       })
+
+      local lspconfig = require('lspconfig')
+
+      -- Common keymaps to run when the Eclipse LSP attaches to a Java buffer
+      local on_attach = function(client, bufnr)
+        local opts = { buffer = bufnr, silent = true }
+        
+        -- Eclipse IDE core features mapped to Neovim actions
+        vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, opts)
+        vim.keymap.set('n', 'gd', vim.lsp.buf.definition, opts)
+        vim.keymap.set('n', 'K', vim.lsp.buf.hover, opts)
+        vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, opts)
+        vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, opts)
+        vim.keymap.set('n', '<leader>rn', vim.lsp.buf.rename, opts)
+        vim.keymap.set('n', '<leader>ca', vim.lsp.buf.code_action, opts)
+        vim.keymap.set('n', 'gr', vim.lsp.buf.references, opts)
+        vim.keymap.set('n', '<leader>f', function() vim.lsp.buf.format { async = true } end, opts)
+      end
+
+      -- Initialize the Eclipse JDTLS Server configuration
+      -- NixOS patches 'jdtls' wrapper script automatically to point to the correct binary paths
+      lspconfig.jdtls.setup({
+        on_attach = on_attach,
+        cmd = { "jdtls" },
+        root_dir = lspconfig.util.root_pattern(".git", "pom.xml", "build.gradle"),
+      })
     '';
 
     plugins = with pkgs.vimPlugins; [
@@ -95,6 +126,7 @@
       { plugin = lualine-nvim; }
       { plugin = neocord; }
       { plugin = gitsigns-nvim; }
+      { plugin = nvim-lspconfig; }
     ];
   };
 }