Set the Number of Visible Items in the Menu of a JComboBox Component in Java

//  ww w .ja v a2 s. c om
import java.awt.BorderLayout;

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

public class Main {
  public static void main(String[] argv) throws Exception {
    JFrame frame = new JFrame("Selecting JComboBox");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    String[] items = new String[50];
    for (int i = 0; i < items.length; i++) {
      items[i] = "" + Math.random();
    }
    JComboBox cb = new JComboBox(items);

    // Retrieve the current max visible rows
    int maxVisibleRows = cb.getMaximumRowCount();

    // Change the current max visible rows
    maxVisibleRows = 20;
    cb.setMaximumRowCount(maxVisibleRows);
    
 
    
    frame.add(cb, BorderLayout.SOUTH);

    frame.setSize(400, 200);
    frame.setVisible(true);
  }
}