src/share/classes/com/sun/java/swing/plaf/windows/WindowsComboBoxUI.java

@@ -405,10 +405,11 @@
         } else {
             return super.createArrowButton();
         }
     }
 
+    @SuppressWarnings("serial") // Superclass is not serializable across versions
     private class XPComboBoxButton extends XPStyle.GlyphButton {
         public XPComboBoxButton() {
             super(null,
                   (! XPStyle.getXP().isSkinDefined(comboBox, Part.CP_DROPDOWNBUTTONRIGHT))
                    ? Part.CP_DROPDOWNBUTTON

@@ -457,10 +458,11 @@
      * Do not call or override.
      *
      * @deprecated As of Java 2 platform v1.4.
      */
     @Deprecated
+    @SuppressWarnings("serial") // Superclass is not serializable across versions
     protected class WindowsComboPopup extends BasicComboPopup {
 
         public WindowsComboPopup( JComboBox cBox ) {
             super( cBox );
         }

@@ -508,10 +510,11 @@
 
     /**
      * Subclassed to set opacity {@code false} on the renderer
      * and to show border for focused cells.
      */
+    @SuppressWarnings("serial") // Superclass is not serializable across versions
     private static class WindowsComboBoxRenderer
           extends BasicComboBoxRenderer.UIResource {
         private static final Object BORDER_KEY
             = new StringUIClientPropertyKey("BORDER_KEY");
         private static final Border NULL_BORDER = new EmptyBorder(0, 0, 0, 0);