No, It not being used directly anywhere in the code, however in Sun JDK it is used by
classes. These Teiid certainly uses them in the code. Are you using Sun JDK? This exception happening during the creation of the jdbc connection?
During the connection time if you are using "File path profile", we do use a post-delegation model to load all the Teiid libraries, and we properly delegate any java or javax classes to higher class loader. The Designer tool uses Teiid in the Eclipse as a plug-in module too, we have not seen this specific issue.
may be you can debug and find the source class which is trying to load this class?