question: private void addReference ( final int sourcePosition , final int referencePosition ) { if ( srcAndRefPositions == null ) { srcAndRefPositions = new int [ 6 ] ; } if ( referenceCount >= srcAndRefPositions . length ) { int [ ] a = new int [ srcAndRefPositions . length + 6 ] ; System . arraycopy ( srcAndRefPositions , 0 , a , 0 , srcAndRefPositions . length ) ; srcAndRefPositions = a ; } srcAndRefPositions [ referenceCount ++ ] = sourcePosition ; srcAndRefPositions [ referenceCount ++ ] = referencePosition ; }
target:  Adds a forward reference to this label. This method must be called only for a true forward reference, i.e. only if this label is not resolved yet. For backward references, the offset of the reference can be, and must be, computed and stored directly.