Package doesn't exists - error!!- How to resolve?

[Niyas Ahmed Sheikh]

Hi,

Below is the folder structure for my development environment:

                      D:              
                      |          
                  MyProjects              
                      |     
              ------beerV1-----------------------        
           /      /     |            \           \      
         etc   lib     src           classes     web       
         |              |                  |      | \_____   
       web.xml         com                com  form.html res.jsp           
                        |                  |              
                     example           example            
                     /     \           |      \              
                   web  model        web    model             
                 _/         |          |         \_____  
   BeerSelect.java  BeerExpert.java BeerSelect.class [B]BeerExpert.class[/B]     

Problem
---------
I am learning MVC and for that I tried to execute the simple program which includes Plain Java Coding(Model), Servlet(Controller) and JSP and HTML(View).

Actually, I want to compile the servlet in which it creates the instance of the class (BeerExpert) and use the method of that class BeerExpert.

While I compiling I am getting the package no found error:

The code I am executing:

Servlet Coding(Controller):

package com.example.web;
 
[B]import com.example.model;[/B]
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
 
public class BeerSelect extends HttpServlet
{
  public class doPost(HttpServletRequest request, HttpServletResponse  response) throws IOException, ServletException
  {
     response.setContentType("text/html");
     PrintWriter out = response.getWriter();
     out.println("Beer Selection Advice<br>");
     String c = request.getParameter("color");
 
     BeerExpert be = new BeerExpert();
     List result = be.getBrands(c);
     Iterator it = result.iterator();
     while(it.hasNext())
     {
       out.println("<br>try: " + it.next());
     }
   }
} 

The Plain Java Code(Model)
It's source file has been kept in
D:\MyProjects\beerV1\src\com\example\model\

and class file in
D:\MyProjects\beerV1\classes\com\example\model\
and
C:\Tomcat\webapps\Beer-v1\WEB-INF\classes\com\example\model

package com.example.model
 
import java.util.*;
 
public class BeerExpert
{
  public List getBrands(String color)
  {
     if(color.equals("amber");
     brands.add("Jack Amber");
     brands.add("Red Moose");
  }
  else
  {
     brands.add("Jail Pale Ale");
     brands.add("Gout Stout");
  }
  return(brands);
 }
}

I compiled the above java coding as below:

For Java - Compiler Option
-----------------------------
D:\MyProjects\beerV1\src>javac -classpath c:\Tomcat\common\lib\servlet-api.jar -d ..\classes \com\example\model\BeerExpert.java

By above the class file for BeerExpert has been automatically placed at D:\MyProjects\beerV1\classes\com\example\model

For Servlet - Compiler Option
-----------------------------
D:\MyProjects\beerV1\src>javac -classpath c:\Tomcat\common\lib\servlet-api.jar -d ..\classes \com\example\web\BeerSelect.java

When I tried to compile the Servlet by same, it's geenrating the error message as
com/example/model pacakge doesn't exists;

Why this error is occuring? How to resolve it?

[Manuel Moons]

You are getting this error because the package can not be found by the compiler.

In order to compile correctly you will have to set the classpath so it includes the "D:\MyProjects\beerV1\classes" folder in which the other classes are located.

So you should start compiling using something like this:

D:\MyProjects\beerV1\src>javac -classpath c:\Tomcat\common\lib\servlet-api.jar;D:\MyProjects\beerV1\classes -d ..\classes \com\example\web\BeerSelect.java

This should fix your problem.

[Layne Lund]

I like Manuel's suggestion since you can type that command from any directory, but in case it doesn't work, you can also change to the classes subdirectory and use your original command.

Layne