Java: Altering UI fonts (Nimbus) doesn't work!

I tried to set global Font to be slightly larger:

UIManager.put("defaultFont", new Font(Font.SANS_SERIF, 0, 16));

...works only for the menu but nothing else (buttons, labels).

I tried to change labels and buttons fonts with

UIManager.put("Button.font", new Font(Font.SANS_SERIF, 0, 16));
UIManager.put("Label.font", new Font(Font.SANS_SERIF, 0, 16));

but the font remains.

The only thing that worked for me was deriving a font:

someButton.setFont(someButton.getFont().deriveFont(16f));

But this is not an option, since this must be done for each element manually.

Note, that deriving a font for UIManager doesn't work either:

UIManager.put("Label.font",
    UIManager.getFont("Label.font").deriveFont(16f));

I tested everything under Linux and Windows: same behavior.

I just can't understand how an API can be so messy. If a method is called setFont(..) then I expect it to set the font. If this method fails to set the font in any thinkable circumstances, then it should be deprecated.

EDIT:
The problem not only applies to Nimbus, but also to the default LAF.

Solution

This works with JDK6 and JDK7. Copy+paste and have fun ;)

Note: for JDK6, change
javax.swing.plaf.nimbus to
com.sun.java.swing.plaf.nimbus.

Code

import java.awt.*;
import java.lang.reflect.*;
import javax.swing.*;
import javax.swing.plaf.nimbus.*;

public class Main {

 public static void main(String[] args)
   throws InterruptedException, InvocationTargetException {

  SwingUtilities.invokeAndWait(new Runnable() {

   @Override
   public void run() {
    try {
     UIManager.setLookAndFeel(new NimbusLookAndFeel() {

      @Override
      public UIDefaults getDefaults() {
       UIDefaults ret = super.getDefaults();
       ret.put("defaultFont",
         new Font(Font.MONOSPACED, Font.BOLD, 16)); // supersize me
       return ret;
      }

     });

     new JFrame("Hello") {

      {
       setDefaultCloseOperation(EXIT_ON_CLOSE);
       setLayout(new FlowLayout(FlowLayout.LEFT));

       setSize(500, 500);
       setLocationRelativeTo(null);

       add(new JLabel("someLabel 1"));
       add(new JButton("someButton 1"));
       add(new JLabel("someLabel 2"));
       add(new JButton("someButton 2"));

       setVisible(true);
      }

     };     
    } catch (Exception ex) {
     throw new Error(ex);
    }
   }

  });
 }

}