Hi Gary, (maybe I didn't follow completely) The sub-string for a 1.0 history file is "Meta VERS" since the first line in 1.0 is 'Meta VERSION="1" .;'. Hence this won't throw the exception. I have a unit test at TestJobHistoryFileParserFactory.java that confirms that we get back a JobHistoryFileParserHadoop1 object when it's a 1.0 file. 
Is that what you were referring to?