treeset

843793

TreeSet<String> s = new TreeSet<String>();
		TreeSet<String> subs = new TreeSet<String>();
		 s.add("a"); s.add("b"); s.add("c"); s.add("d"); s.add("e");
		
		 subs = (TreeSet) s.subSet("b",true, "d",true);  //1
		 
		 System.out.println(s +" "+ subs);

in line 1 it returns navigableSet but it is casted to treeset which is a subclass of navigableset so
why doesn't it returns classcastexception?

Kayaman

Because its actual class is TreeSet. The Set interface just defines subSet to return NavigableSet.

843793

you mean the object returned is treeset bysubset

Kayaman

Yes. Otherwise you'd get a ClassCastException.
But as far as the Set interface is concerned, it needs to return a NavigableSet.

Of course you can't rely on subSet always returning a TreeSet, you understand that don't you?