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import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.event.ItemEvent;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.plaf.nimbus.NimbusLookAndFeel;

public class DemoSwing extends JFrame {

    private JComboBox<String> comboBox = new JComboBox<>( new String[] { "First", "Second", "Third" } );
    private JScrollPane tree = new JScrollPane( new JTree() );
    private JScrollPane textArea = new JScrollPane( new JTextArea("Content to edit") );
    private JButton button = new JButton( "Click Me" );
    private JPanel contentPane;
    
    private Component currentInjectedComponent = null;
    
    public DemoSwing() {
        super( "Demo changement contenu" );
        this.setSize( 400, 300 );
        this.setLocationRelativeTo( null );
        this.setDefaultCloseOperation( DISPOSE_ON_CLOSE );
        
        contentPane = (JPanel) getContentPane();
        contentPane.add( comboBox, BorderLayout.NORTH );
        
        // Utilisation de référence sur méthode pour la gestion des événements (requière un Java SE 8)
        comboBox.addItemListener( this::comboBoxItemStateChange );
        
        this.setVisible( true );
    }
    
    public void comboBoxItemStateChange( ItemEvent event ) {
        if ( event.getStateChange() == ItemEvent.SELECTED ) {
            if ( currentInjectedComponent != null ) {
                contentPane.remove( currentInjectedComponent );
            }
            switch( (String) event.getItem() ) {
                case "First":
                    currentInjectedComponent = tree;
                    contentPane.add( tree, BorderLayout.CENTER );
                    break;
                case "Second":
                    currentInjectedComponent = textArea;
                    contentPane.add( textArea, BorderLayout.CENTER );
                    break;
                default:
                    currentInjectedComponent = button;
                    contentPane.add( button, BorderLayout.CENTER );
            }
            contentPane.revalidate();
            currentInjectedComponent.repaint();
        }
    }
    
    
    public static void main( String[] args )  throws Exception {
        UIManager.setLookAndFeel( new NimbusLookAndFeel() );
        new DemoSwing();
    }
    
}