Java - Quitar flecha a JCOMBOBOX

import java.awt.Component;

import java.awt.Container;

import javax.swing.AbstractButton;

import javax.swing.JComboBox;

import javax.swing.JOptionPane;

public class PlayWithComboArrow {

   public static void main(String[] args) {

      String[] items = {"Fe", "Fi", "Fo", "Fum"};

      JComboBox<String> combo = new JComboBox<String>(items);

      combo.setEditable(true);

      removeButton(combo);

      JOptionPane.showMessageDialog(null, combo);

   }

   private static void removeButton(Container container) {

      Component[] components = container.getComponents();

      for (Component component : components) {

         if (component instanceof AbstractButton) {

            container.remove(component);

         }

      }

   }

}