Ошибка при выполнении примера из «Философии Java»

//: object/HelloDate.java
package object; /* Added by Eclipse.py */
import java.util.*;

/** The first Thinking in Java example program.
 * Displays a string and today's date.
 * @author Bruce Eckel
 * @author www.MindView.net
 * @version 4.0
*/
public class HelloDate {
  /** Entry point to class & application.
   * @param args array of string arguments
   * @throws exceptions No exceptions thrown
  */
  public static void main(String[] args) {
    System.out.println("Hello, it's: ");
    System.out.println(new Date());
  }
} /* Output: (55% match)
Hello, it's:
Wed Oct 05 14:39:36 MDT 2005
*///:~

Exception in thread "main" java.lang.NoClassDefFoundError: HelloDate/class
Caused by: java.lang.ClassNotFoundException: HelloDate.class
        at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: HelloDate.class. Program will exit.