JComboBox() constructor from JComboBox has the following syntax.
public JComboBox()
In the following code shows how to use JComboBox.JComboBox() constructor.
/*from www.ja va2s.c o m*/ import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import javax.swing.Icon; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel implements ItemListener { public Main() { JComboBox jc = new JComboBox(); jc.addItem("France"); jc.addItem("Germany"); jc.addItem("Italy"); jc.addItem("Japan"); jc.addItemListener(this); add(jc); } public void itemStateChanged(ItemEvent ie) { String s = (String)ie.getItem(); System.out.println(s); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.getContentPane().add(new Main()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(200, 200); frame.setVisible(true); } }