SAXCatalogReader supports two modes: a legacy mode where it is created with a saxParserClass name, and a new mode where it is created with a saxParserFactory.

In the JDK, it appears that the saxParserClass mode is not used (saxParserClass is always null).

SAXCatalogReader should be cleened up and the protected saxParserClass variable could therefore be removed alongside all the code that deals with it.