question: private final int compare ( Comparable item , RedBlackNode t ) { if ( t == header ) return 1 ; else return item . compareTo ( t . element ) ; }
target:  Compare item and t.element, using compareTo, with caveat that if t is header, then item is always larger. This routine is called if is possible that t is header. If it is not possible for t to be header, use compareTo directly.