Java tutorial
import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JSplitPane; public class Main { public static void main(String[] a) { JFrame horizontalFrame = new JFrame(); horizontalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComponent leftButton = new JButton("Left"); JComponent rightButton = new JButton("Right"); JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT); splitPane.setLeftComponent(leftButton); splitPane.setRightComponent(rightButton); horizontalFrame.add(splitPane, BorderLayout.CENTER); horizontalFrame.setSize(150, 150); horizontalFrame.setVisible(true); } }