I am trying to attach Javadoc API URL to Weblogic System Libraries (Java EE API) but it not works. The Weblogic System Libraries is added to your Project's Build Path when you add some JavaEE facet and add the it to aWLS Runtime configured on OEPE.
After edit the Weblogic System Library eclipse change the .classpah file but the Javadoc does not appears on Eclipse editor.
See my .classpath snippet after configure the JavaEE6 API URL to the javax.jms_1.1.2.jar in Weblogic System Libraries:
This is a bug. You shouldn't need to attach javadoc manually like this. We will address this for the next release. Unfortunately, I don't have a workaround for you in the meantime. Manually attach it will not work as you found out.