I installed the Groovy Console. It's a pretty nifty and easy way to quickly run some java that you need to quickly iterate through the write/test/fix cycle.
I was trying to parse some html into xml, and I got the following error:
java.lang.NoClassDefFoundError: org/apache/xerces/parsers/AbstractSAXParser
I tried adding 3 different versions of xercesImpl to my Groovy Console classpath, to no avail. While adding to the groovy classpath worked for some jars (i.e. commons-io), it did not work for the xercesImpl jar.