Followups directed to comp.lang.java.programmer.
what may be a cause for a ClassCircularityError if there is no
circularity in the class hierarchy of an Eclipse Plug-In? The error
occurs when invoking methods of an object of another plug-in.
I am unaware of any circumstance in which a ClassCircularityError in the
absence of an actual class circularity would be anything but a VM bug.
Class circularity is defined as a class being one of its own
superclasses, or an interface being one of its own superinterfaces. It
is difficult, but not impossible, to achieve this result with a
conformant Java compiler; the technique would involve compiling a class
hierarchy, modifying it in such a way that at least one ancestry
relationship changes direction, and then compiling the hierarchy again
to seperate class files. If both collections of class files are
available to the system at runtime then a ClassCircularityError may
arise when the VM attempts to satisfy class loading requirements from
both collections of class files instead of from just one or just the other.
Given that you're talking about interaction between two different
plug-ins, a scenario similar to what I described seems fairly
reasonable. There may be no circularity in either plug-in individually
(and I wouldn't expect there to be), but there might be one in the
combination of the two (or more).
John Bollinger
(e-mail address removed)
