Very rarely problems may be encountered with classes that have been load-time woven. Symptoms will include incorrect program function or a Java exception such as java.lang.VerifyError. In these situations it's most helpful to include the offending class in the bug report. When using load-time weaving the woven classes are in memory only so to save them to disk configure META-INF/aop.xml to dump the classes (by default to an _ajdump subdirectory of the current working directory). Also if the input class file is not available (e.g. it is a generated proxy or has already been instrumented by another agent) you can configure the weaver to dump the input classes as well. For details of how to configure byte-code dumping, see the AspectJ Development Environment Guide section on Configuring Load-time Weaving. Following is a simple example. The following META-INF/aop.xml will weave classes in the com.foo package (and subpackages) but not CGLIB generated classes in the com.foo.bar package (and subpackages). It will also ensure all woven byte-code is dumped both before and after weaving. ]]> You should see messages similar to this: On disk you would find the following files: