新手求助！！ - 编程论坛

按照书上写的运行顺序
程序如下
package
import javax.servlet.*;
import javax.servlet.http.*;
import *;
public class HelloServlet extends HttpServlet {

//Initialize global variables
public void init(ServletConfig config) throws ServletException {
  super.init(config);
}

//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  response.setContentType("text/html;charset=GB2312");
  PrintWriter out = response.getWriter();

  out.println("<html>");
  out.println("<head><title>CH2 - HelloServlet</title></head>");
  out.println("<body>");
  out.println(" Hello World <br>");
  out.println("大家好");
  out.println("</body>");
  out.println("</html>");
  out.close();
}

//Get Servlet information
public String getServletInfo() {
  return " Information";
}
}

运行javac HelloServlet.java没有问题
但运行java HelloServlet时出现 Exception   in   thread   "main"   java.lang.noclassdefoundErrorException in thread "main" java.lang.NoClassDefFoundError: HelloServlet (wrong name: tw/com/javaworld/CH2/HelloServlet)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
        at (URLClassLoader.java:260)
        at (URLClassLoader.java:56)
        at (URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at (URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)

请高手指点！