Check out example codes for "set java". It will help you in understanding the concepts better.

Code Example 1

import java.util.*;
public class SetDemo {

  public static void main(String args[]) { 
      int count[] = {34, 22,10,60,30,22};
      Set<Integer> set = new HashSet<Integer>();
      try {
         for(int i = 0; i < 5; i++) {
            set.add(count[i]);
         }
         System.out.println(set);

         TreeSet sortedSet = new TreeSet<Integer>(set);
         System.out.println("The sorted list is:");
         System.out.println(sortedSet);

         System.out.println("The First element of the set is: "+ (Integer)sortedSet.first());
         System.out.println("The last element of the set is: "+ (Integer)sortedSet.last());
      }
      catch(Exception e) {}
   }
} 

OUTPUT:

              [34, 22, 10, 60, 30]
              The sorted list is:
              [10, 22, 30, 34, 60]
              The First element of the set is: 10
              The last element of the set is: 60

Code Example 2

A Set is a Collection that cannot contain duplicate elements.
  
The Set interface contains only methods inherited from Collection 
and adds the restriction that duplicate elements are prohibited.

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