Swing transferFocus use setFocusTraversalKeys

import java.awt.Container;
import java.awt.KeyboardFocusManager;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.util.HashSet;
import java.util.Set;
import javax.swing.KeyStroke;

public class Main extends javax.swing.JFrame {
    
    public Main() {
        initComponents();
        forwardWithEnter(this);
        backwardWithShiftEnter(this);          
    }
    
    private void setFocusTraversalKey(int id, KeyStroke keystroke, Container container) {
        Set set = this.getFocusTraversalKeys(id);
        set = new HashSet(set);
        set.add(keystroke);
        container.setFocusTraversalKeys(id, set);
    }
    
    private void forwardWithEnter(Container container){
        KeyStroke keystroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0);
        int id = KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS;
        setFocusTraversalKey(id, keystroke, container);        
    }
    
    private void backwardWithShiftEnter(Container container){
        KeyStroke keystroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, InputEvent.SHIFT_MASK);
        int id = KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS;
        setFocusTraversalKey(id, keystroke, container);             
    }    

    @SuppressWarnings("unchecked")
    // 
    private void initComponents() {

        jTextField1 = new javax.swing.JTextField();
        jTextField2 = new javax.swing.JTextField();
        jTextField3 = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jTextField1.setText("forward: Enter");
        getContentPane().add(jTextField1, java.awt.BorderLayout.PAGE_START);

        jTextField2.setText("backward: Shift + Enter");
        getContentPane().add(jTextField2, java.awt.BorderLayout.CENTER);

        jTextField3.setText("jTextField3");
        getContentPane().add(jTextField3, java.awt.BorderLayout.PAGE_END);

        pack();
    }// 

    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Main().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    private javax.swing.JTextField jTextField3;
    // End of variables declaration

}