ConcurrentSkipListSet.first()

// Java Program Demonstrate first()
// method of ConcurrentSkipListSet
  
import java.util.concurrent.ConcurrentSkipListSet;
  
class ConcurrentSkipListSetFirstExample1 {
    public static void main(String[] args)
    {
  
        // Initializing the set
        ConcurrentSkipListSet<Integer>
            set = new ConcurrentSkipListSet<Integer>();
  
        // Adding elements to first set
        set.add(10);
        set.add(35);
        set.add(20);
        set.add(25);
  
        System.out.println("The lowest element in the set: "
                                              + set.first());
    }
}

The lowest element in the set: 10

// Java Program Demonstrate first()
// method of ConcurrentSkipListSet
  
import java.util.concurrent.ConcurrentSkipListSet;
  
class ConcurrentSkipListSetFirstExample2 {
    public static void main(String[] args) throws InterruptedException
    {
  
        // Initializing the set
        ConcurrentSkipListSet<Integer>
            set = new ConcurrentSkipListSet<Integer>();
        try {
            System.out.println("The lowest element in the set: " +
                                                       set.first());
        }
        catch (Exception e) {
            System.out.println("Exception :" + e);
        }
    }
}

Exception :java.util.NoSuchElementException