Camel's GroovyLanguage maintains a cache of Groovy class scripts up to maximum of 1000 entries. When the limit of 1000 entries is reached the LRU cache removes the least used ones.
The LRU cache removes only the Script classes it does not remove all the references that still remain to that class and this causes a memory leak.
The remaining references are in Groovy metaclass registry, Groovy ClassInfo reflection support cache and Java Beans Introspector cache.
All of these can be easily removed on removal from the Camel LRU script cache by invoking org.codehaus.groovy.runtime.InvokerHelper.removeClass.
See Groovy and Camel PermGen troubles with Java 1.7 on the camel-users mailing list.