import java.util.Arrays;
import java.util.Set;
import java.util.TreeSet;
 public class Javaexcercise
{
 
   public static void main(String[] args) 
    {
       Integer[] numbers = {1, 1, 2, 1, 3, 4, 5};
    Set<Integer> uniqKeys = new TreeSet<Integer>();
    uniqKeys.addAll(Arrays.asList(numbers));
    System.out.println("uniqKeys: " + uniqKeys);
    }
}

Result