From: <glassfish_at_javadesktop.org>
Date: Tue, 30 Sep 2008 06:36:33 PDT
It looks to me like you have imported a trusted certificate entry into the keystore (as apposed to a key entry). A key entry contains both the private and public key, where a trusted cert entry contains only the latter.
JDK 6. enhanced the keytool command so that you can use it to import key entries into a keystore. You can use the keytool binary that ships with JDK 6 to add a key entry to a JDK 5 keystore.