Java by API/java.util/EmptyStackException

EmptyStackException as a type

/*
 * Output:
 * 
stack: []
push(42)
stack: [42]
pop -> 42
stack: []
empty stack

 *  
 */
import java.util.Stack;
import java.util.EmptyStackException;
public class MainClass {
  public static void main(String args[]) {
    Stack st = new Stack();
    System.out.println("stack: " + st);
    st.push(new Integer(42));
    System.out.println("push(" + 42 + ")");
    System.out.println("stack: " + st);
    System.out.print("pop -> ");
    Integer a = (Integer) st.pop();
    System.out.println(a);
    System.out.println("stack: " + st);
    try {
      st.pop();
    } catch (EmptyStackException e) {
      System.out.println("empty stack");
    }
  }
}