In jnlp , specify three icons with different kind attribute: "default" "splash" "shortcut",like
      <icon href="images/BLUE.png" kind="default" />
      <icon href="images/RED.png" kind="splash"/>
      <icon href="images/YELLOW.png" kind="shortcut"/>
The specified icon will not shown in Java Cache Viewer if invoke cache viewer from the Java Control Panel (not from javaws -viewer) on windows

Steps:
1)javaws -uninstall (just to make sure that there are no cached apps)
2)javaws -import http://sceri.prc/~yl153753/IconTest/test_allkinds.jnlp
3)Goto Start -> Control Panel -> Java (Launch Java Control Panel)
4)Click on "View" to launch Java Cache Viewer , the "Icon Test 5" application has javacup icon

JRE Version:
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b39)
Java HotSpot(TM) Client VM (build 1.6.0-ea-b39, mixed mode, sharing)

###@###.### 2005-06-07 08:42:51 GMT