Useful if you want to let the user choose the font to use for certain components of a Swing UI:

package net.doepner.ui.text;

import java.awt.Component;
import java.awt.Font;
import java.awt.GraphicsEnvironment;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.Arrays;
import java.util.Comparator;

import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JList;
import javax.swing.ListCellRenderer;

public class FontChooser extends JComboBox<Font> {

	public FontChooser(final Component... components) {

		final Font[] fonts = GraphicsEnvironment
				.getLocalGraphicsEnvironment()
				.getAllFonts();

		Arrays.sort(fonts, new Comparator<Font>() {
			@Override
			public int compare(Font f1, Font f2) {
				return f1.getName().compareTo(f2.getName());
			}
		});

		for (Font font : fonts) {
			if (font.canDisplayUpTo(font.getName()) == -1) {
				addItem(font);
			}
		}

		addItemListener(new ItemListener() {
			@Override
			public void itemStateChanged(ItemEvent e) {
				final Font font = (Font) e.getItem();
				for (Component comp : components) {
					setFontPreserveSize(comp, font);
				}
			}
		});
		
		setRenderer(new FontCellRenderer());
	}
	
	private static class FontCellRenderer 
			implements ListCellRenderer<Font> {
		
		protected DefaultListCellRenderer renderer = 
				new DefaultListCellRenderer();
		
		public Component getListCellRendererComponent(
				JList<? extends Font> list, Font font, int index, 
				boolean isSelected, boolean cellHasFocus) {
			
			final Component result = renderer.getListCellRendererComponent(
					list, font.getName(), index, isSelected, cellHasFocus);
			
			setFontPreserveSize(result, font);
			return result;
		}
	}

	private static void setFontPreserveSize(final Component comp, Font font) {
		final float size = comp.getFont().getSize();
		comp.setFont(font.deriveFont(size));
	}
}

I recently posted some reusable code that facilitates reverse iteration over a list in Java.

Here is another potentially useful Java method related to iteration, from my buddy Jordan Armstrong:

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

  /**
   * @param n An XML node list
   * @return A newly created Iterable for the given node list, allowing 
   *         iteration over the nodes in a for-each loop. The iteration 
   *         behavior is undefined if concurrent modification of the node list
   *         occurs.
   */
  public static Iterable<Node> iterable(final NodeList n) {
    return new Iterable<Node>() {

      @Override
      public Iterator<Node> iterator() {

        return new Iterator<Node>() {

          int index = 0;

          @Override
          public boolean hasNext() {
            return index < n.getLength();
          }

          @Override
          public Node next() {
            if (hasNext()) {
              return n.item(index++);
            } else {
              throw new NoSuchElementException();
            }  
          }

          @Override
          public void remove() {
            throw new UnsupportedOperationException();
          }
        };
      }
    };
  }