src/java.desktop/unix/classes/sun/awt/X11/XTaskbarPeer.java

*** 101,110 ****
--- 101,112 ----
          if (badge != null) {
              try {
                  val = Long.parseLong(badge);
                  visible = true;
              } catch (NumberFormatException e) {
+                 throw new UnsupportedOperationException("The " + Feature.ICON_BADGE_TEXT
+                     + " feature is not supported on the current platform!");
              }
          }
          setBadge(val, visible);
      }