JComboBox

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JTextArea;

public class Guj extends JFrame implements ItemListener {

	private JComboBox box ;
	private JTextArea area;
	private String[] carros = { "gol", "palio" , "vectra" };
	private String[] gol = { "porta do gol " , " pneu do gol " };
	private String[] palio = { "porta do palio " , " pneu do palio " };
	private String[] vectra ={ "porta do vectra " , " pneu do vectra " };
	
	
	public Guj(){
		
		box = new JComboBox( carros );
		area = new JTextArea( 10 ,20);
		
		Container container = getContentPane();
		container.setLayout( new FlowLayout());
		
		container.add( box );
		container.add( area );
		
		box.addItemListener( this );
		
		setSize( 250, 200 );
		setVisible( true );
		
		
	}
	
	public static void main( String[] args ){
		
		Guj guj = new Guj();
		
		guj.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	}

	public void itemStateChanged(ItemEvent e) {
		
		if( e.getSource() == box ){
			
			// Seleciona o Gol  
			if( box.getSelectedIndex() == 0){
				
				area.setText( "" );
				
				for (int i = 0; i < gol.length; i++) {
					
					area.append( gol[i] + "\n" );
				}
			}
			// Seleciona o Palio  
			else if( box.getSelectedIndex() == 1){
				
				area.setText( "" );
				
				for (int i = 0; i < palio.length; i++) {
					
					area.append( palio[i] + "\n" );
				}
			}
			//Seleciona o Vectra  
			else if( box.getSelectedIndex() == 2){
				
				area.setText( "" );
				
				for (int i = 0; i < vectra.length; i++) {
					
					area.append( vectra[i] + "\n" );
				}
			}
		}
	}
}