Question About TreeSet?

[Afzal Rehman]

  import java.util.*;

public class TestSet {
    static void add(Set<? super String> set) {
        set.add("Hi");
        set.add("Hi");
        System.out.println(set.size());
    }
    public static void main(String[] args) {
        Set<String> set = new HashSet<String>();
        add(set);
    }
}
  

Why Output is 1? ,

[Henry Wong]

First, you example uses a HashSet -- not a TreeSet.... To answer your question, Sets don't allow duplicates.

Henry

[Brij Garg]

Add method will return false if the object it is adding to the set is already there in the set.

[bhanu chowdary]

HashSet won't allow duplicates.