I was writing an iterator that takes advantage of some classes in Google's guava-libraries. I placed my jar and the guava-13.0-rc2.jar into lib/ext.
I then ran a simple Java class which opened a Scanner to a table with my customer Iterator in Eclipse. The first attempt succeeded. I then changed my iterator, recompiled the jar, and placed it in lib/ext. The AccumuloClassLoader message said it picked up the changes. Then, trying to run my class in the same manner, I got a java.lang.LinkageError relating to the classloader having two different Class objects for a class defined in the guava jar (which hadn't changed).
Moving the guava jar from lib/ext to lib/ and retrying this experiment did not net the same LinkageError.
I'll attach full stack traces and the output of `accumulo classpath`