package basics.checkargs;
public class Main {
  private Main() {}
  static public void main (final String[] args) {
    //stdlib.Trace.graphvizShowSteps (true); stdlib.Trace.run ();
    try {
      System.out.println(new Person("bob"));
      System.out.println(new Person(null));
    } catch (IllegalArgumentException e) {
      System.out.println("Error creating Person: " + e); 
    }
  }
}
final class Person {
  final private String name;
  public Person(String name) {
    if (name == null)
      throw new IllegalArgumentException("null name");
    this.name = name;
  }
  public String toString() { return "Person(" + name + ")"; };
}