question: private static Comparable < ? > castToComparable ( Object obj ) { try { return ( Comparable < ? > ) obj ; } catch ( ClassCastException cce ) { throw new IllegalArgumentException ( "Type " + obj . getClass ( ) + " doesn't implement Comparable, Serialization mode might be different than " + StorageType . OBJECT + "." , cce ) ; } }
target:  Cast the object to Comparable otherwise throws an IllegalArgumentException exception