question: public static < U > AtomicIntegerFieldUpdater < U > newUpdater ( Class < U > tclass , String fieldName ) { if ( UnsafeHolder . isAvailable ( ) ) { return new AtomicIntegerFieldUpdaterImpl < U > ( tclass , fieldName ) ; } return AtomicIntegerFieldUpdater . newUpdater ( tclass , fieldName ) ; }
target:  Creates an updater for objects with the given field.  The Class argument is needed to check that reflective types and generic types match.