Conditions signaled when an argument that needs to be a Java object is not a jobject or an instance of standard-java-object.
The condition class java-not-a-java-object-error
is signaled when an argument that needs to be a Java object is not a jobject or an instance of standard-java-object.
You can use the java-bad-jobject readers java-bad-jobject-caller
and java-bad-jobject-object
on these conditions.
LispWorks User Guide and Reference Manual - 13 Feb 2015