[hardwired]

TextAction was designed for this. The nested classes in DefaultEditorKit extend it.

Code:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;

public class TextFocus {
    private JMenuBar getMenuBar() {
        JMenu menu = new JMenu("edit");
        //DefaultEditorKit kit = new DefaultEditorKit();
        //Action[] actions = kit.getActions();
        //for(int i = 0; i < actions.length; i++)
        //    System.out.println(actions[i].getValue(Action.NAME));
        Action action = new DefaultEditorKit.CutAction();
        action.putValue(Action.NAME, "cut");
        menu.add(action);
        action = new DefaultEditorKit.CopyAction();
        action.putValue(Action.NAME, "copy");
        menu.add(action);
        action = new DefaultEditorKit.PasteAction();
        action.putValue(Action.NAME, "paste");
        menu.add(action);
        menu.add(new SelectAction());
        JMenuBar menuBar = new JMenuBar();
        menuBar.add(menu);
        return menuBar;
    }

    private class SelectAction extends TextAction {
        SelectAction() {
            super(DefaultEditorKit.selectAllAction);
            super.putValue(NAME, "selectAll");
        }

        public void actionPerformed(ActionEvent e) {
            getFocusedComponent().selectAll();
        }
    }

    private JPanel getContent() {
        String[] strs = {
            "red", "green", "yellow", "blue"
        };
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        for(int i = 0; i < 4; i++) {
            JTextField tf = new JTextField(strs[i], 12);
            gbc.gridwidth = ((i+1) % 2 == 0) ? gbc.REMAINDER : 1;
            panel.add(tf, gbc);
        }           
        return panel;
    }

    public static void main(String[] args) {
        TextFocus test = new TextFocus();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setJMenuBar(test.getMenuBar());
        f.add(test.getContent());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}