ADVANCE JAVA

      SwingUtilities.invokeLater(new Runnable(){
              public void run(){
        }
        });

        JFrame frame = new JFrame ("lalala");
        frame.setSize(500, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

//create a second jframe in defaultpackage
advancejavapackage criar novo pacote java
create new jframe
//visual guide layout netbeans components
//window builder netbeans
//swing visual guide

public MainFrame(String title) {
 super(title);
// set layout manager
setLayout(new BorderLayout());

// create swing component
JtextArea textArea = new JtextArea();
Jbutton button = new JButtton("click me");

// add swing component to content pane
Container c = getContentPane();

c.add(textArea, BorderLayout.CENTER);
c.add(button, BoderLayout.SOUTH);

//behaviour
button.addActionListener(new ActionListener()  {

@Override
public void actionPerformed(ActionEvent e) {
      textArea.append("hello");

});

  }
}