what does the meaning of "#" in the hashset code example

Example: hashset in java

Let’s see java hashset example.

import java.util.HashSet;
public class HashSetExample
{
   public static void main(String[] args)
   {
      HashSet<String> hs = new HashSet<>();
      hs.add("Banana");
      hs.add("Orange");
      hs.add("Apple");
      hs.add("Pineapple");
      hs.add("Mango");
      System.out.println(hs);
   }
}