Unified Tool Bar Sample Code

import java.awt.BorderLayout;
import java.awt.Container;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.UIManager;

public class SampleToolBar {
  private ToolBarButton fileButton
    = new ToolBarButton("File", UIManager.getIcon("FileView.fileIcon"));
  private ToolBarButton folderButton
    = new ToolBarButton("Folder", UIManager.getIcon("FileView.directoryIcon"));

  public SampleToolBar() {
    JToolBar tb = new JToolBar();
    tb.setFloatable(false);
    tb.add(fileButton);
    tb.add(folderButton);

    JFrame fr = new JFrame("Sample Tool Bar");
    fr.getRootPane().putClientProperty("Aqua.windowStyle", "unifiedToolBar");
    Container cp = fr.getContentPane();
    cp.setLayout(new BorderLayout());
    cp.add(tb, BorderLayout.NORTH);
    cp.add(new JPanel());
    fr.setSize(300, 200);
    fr.setVisible(true);
  }

  private class ToolBarButton extends JButton {
    public ToolBarButton(String text, Icon icon) {
      setIcon(icon);
      setText(text);
      setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);
      setVerticalTextPosition(javax.swing.SwingConstants.BOTTOM);
      //putClientProperty("JComponent.sizeVariant", "small");
    }
  }
}