public void insert(double x1,double x2,Object item){
  super.insert(new Interval(Math.min(x1,x2),Math.max(x1,x2)),item);
}

public void insert ( double x1 , double x2 , Object item ) { super . insert ( new Interval ( Math . min ( x1 , x2 ) , Math . max ( x1 , x2 ) ) , item ) ; }
inserts an item having the given bounds into the tree .
