Java by API/javax.swing.plaf.basic/BasicArrowButton

new BasicArrowButton(BasicArrowButton.EAST)

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.plaf.basic.BasicArrowButton;
public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame("Popup JComboBox");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new BasicArrowButton(BasicArrowButton.NORTH), BorderLayout.NORTH);
    frame.add(new BasicArrowButton(BasicArrowButton.EAST), BorderLayout.EAST);
    frame.add(new BasicArrowButton(BasicArrowButton.SOUTH), BorderLayout.SOUTH);
    frame.add(new BasicArrowButton(BasicArrowButton.WEST), BorderLayout.WEST);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

new BasicArrowButton(BasicArrowButton.NORTH)

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.plaf.basic.BasicArrowButton;
public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame("Popup JComboBox");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new BasicArrowButton(BasicArrowButton.NORTH), BorderLayout.NORTH);
    frame.add(new BasicArrowButton(BasicArrowButton.EAST), BorderLayout.EAST);
    frame.add(new BasicArrowButton(BasicArrowButton.SOUTH), BorderLayout.SOUTH);
    frame.add(new BasicArrowButton(BasicArrowButton.WEST), BorderLayout.WEST);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

new BasicArrowButton(BasicArrowButton.SOUTH)

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.plaf.basic.BasicArrowButton;
public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame("Popup JComboBox");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new BasicArrowButton(BasicArrowButton.NORTH), BorderLayout.NORTH);
    frame.add(new BasicArrowButton(BasicArrowButton.EAST), BorderLayout.EAST);
    frame.add(new BasicArrowButton(BasicArrowButton.SOUTH), BorderLayout.SOUTH);
    frame.add(new BasicArrowButton(BasicArrowButton.WEST), BorderLayout.WEST);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

new BasicArrowButton(BasicArrowButton.WEST)

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.plaf.basic.BasicArrowButton;
public class MainClass {
  public static void main(final String args[]) {
    JFrame frame = new JFrame("Popup JComboBox");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new BasicArrowButton(BasicArrowButton.NORTH), BorderLayout.NORTH);
    frame.add(new BasicArrowButton(BasicArrowButton.EAST), BorderLayout.EAST);
    frame.add(new BasicArrowButton(BasicArrowButton.SOUTH), BorderLayout.SOUTH);
    frame.add(new BasicArrowButton(BasicArrowButton.WEST), BorderLayout.WEST);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}