Setting the Default Font of Swing Program

try:

public static void setUIFont (javax.swing.plaf.FontUIResource f){
    java.util.Enumeration keys = UIManager.getDefaults().keys();
    while (keys.hasMoreElements()) {
      Object key = keys.nextElement();
      Object value = UIManager.get (key);
      if (value instanceof javax.swing.plaf.FontUIResource)
        UIManager.put (key, f);
      }
    } 

Call by ...

setUIFont (new javax.swing.plaf.FontUIResource("Serif",Font.ITALIC,12));

UIManager.put("Button.font", /* font of your liking */);
UIManager.put("ToggleButton.font", /* font of your liking */);
UIManager.put("RadioButton.font", /* font of your liking */);
UIManager.put("CheckBox.font", /* font of your liking */);
UIManager.put("ColorChooser.font", /* font of your liking */);
UIManager.put("ComboBox.font", /* font of your liking */);
UIManager.put("Label.font", /* font of your liking */);
UIManager.put("List.font", /* font of your liking */);
UIManager.put("MenuBar.font", /* font of your liking */);
UIManager.put("MenuItem.font", /* font of your liking */);
UIManager.put("RadioButtonMenuItem.font", /* font of your liking */);
UIManager.put("CheckBoxMenuItem.font", /* font of your liking */);
UIManager.put("Menu.font", /* font of your liking */);
UIManager.put("PopupMenu.font", /* font of your liking */);
UIManager.put("OptionPane.font", /* font of your liking */);
UIManager.put("Panel.font", /* font of your liking */);
UIManager.put("ProgressBar.font", /* font of your liking */);
UIManager.put("ScrollPane.font", /* font of your liking */);
UIManager.put("Viewport.font", /* font of your liking */);
UIManager.put("TabbedPane.font", /* font of your liking */);
UIManager.put("Table.font", /* font of your liking */);
UIManager.put("TableHeader.font", /* font of your liking */);
UIManager.put("TextField.font", /* font of your liking */);
UIManager.put("PasswordField.font", /* font of your liking */);
UIManager.put("TextArea.font", /* font of your liking */);
UIManager.put("TextPane.font", /* font of your liking */);
UIManager.put("EditorPane.font", /* font of your liking */);
UIManager.put("TitledBorder.font", /* font of your liking */);
UIManager.put("ToolBar.font", /* font of your liking */);
UIManager.put("ToolTip.font", /* font of your liking */);
UIManager.put("Tree.font", /* font of your liking */);

Source: http://www.jguru.com/faq/view.jsp?EID=340519

java -Dswing.aatext=true -Dswing.plaf.metal.controlFont=Tahoma -Dswing.plaf.metal.userFont=Tahoma …

This will not only set Tahoma on your complete UI but also turn on anti-aliasing which makes any font much more beautiful immediately.