java.lang.ClassNotFoundException: arjuncodes.DemoServlet

[Khushi Sing]

Hi,

I am using latest JRE 21 and latest eclipse EE.

My project Structure:

-Java Resources
  >src/main/java
     >arjun codes
        >DemoServlet.java
-src
 >main
       >java
         >arjuncodes
           >DemoServlet.java
       >webapp
          >META-INF
          >WEB-INF
              >lib
              >web.xml
          >index.jsp

codes:

index.jsp

<form action = "add">

<h1>Demo JSP Servlet Program</h1>

Enter the first number: <input type = "text" name = "num1"> 
<br />
Enter the second number: <input type = "text" name = "num2"> <br />

<input type = "submit">

</form>

DemoServlet.java

public class DemoServlet extends HttpServlet
{

	public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException
	{
		
		System.out.println("In DemoServlet");
		int i = Integer.parseInt(req.getParameter("num1"));
		int j = Integer.parseInt(req.getParameter("num2"));
		
		int k = i+j;
		
		PrintWriter out = res.getWriter();
		
		out.println("Result "+ k);
		
	}
	
}

web.xml

within <web-app>:

<servlet>
 	
 	<servlet-name>abc</servlet-name>
 	<servlet-class>arjuncodes.DemoServlet</servlet-class>

</servlet>
 
 
 <servlet-mapping>
 <servlet-name>abc</servlet-name>
 <url-pattern> /add</url-pattern>
 
 </servlet-mapping>

Error: When i enter 2 numbers and then click on submit, this is the error:

Error in browser: Description The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.


Error in eclipse debugger:
java.lang.ClassNotFoundException: arjuncodes.DemoServlet

Conclusion: clearly its not able to find DemoServlet class, but I cant figure out what else path name i could have given in <servlet-class> in web.xml (refer the code above for web.xml).

I am learning servlets and jsp so please bear with me.

Much thanks and Regards

I am expecting that after clicking on submit, it should redirect to page and sum should be written on this new redirected page

[Stephan van Hulst]

Did you put a package statement above your servlet class?

[Khushi Sing]

Yes I have added package statement

package arjuncodes;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DemoServlet extends HttpServlet{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException {
int i=Integer.parseInt(req.getParameter("num1"));
int j=Integer.parseInt(req.getParameter("num2"));
int k=i+j;
PrintWriter out=res.getWriter();
out.println("Result is "+k);
}
}

[Tim Moores]

You're only showing the directory layout of the source code. After building the project, is the DemoServlet.class file in the directory WEB-INF/classes/arjuncodes?

[Tim Holloway]

Since you've arranged your project in Maven format, what Maven goal(s) are you invoking?

[Roland Mueller]

Just a wild guess (5 min before midnight):

Can it be that in your web project older servlets from javax.* packages are used and the test server in Eclipse has already new jakarta JavaWeb setup? I don't recall what error messages one gets in this case i.e. whether the exception is java.lang.ClassNotFoundException.