javax.servlet.ServletException: Wrapper cannot find servlet class

[Farakh khan]

Hello,

The following is my class code: the code don't have any error and class resides in package globalcategories.classes

package globalcategories.classes;
import common.classes.ErrorCheck;
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

	
public class GlobalCategoriesManager extends HttpServlet {


	String title =""; String tableName=""; String colName="";

	public GlobalCategoriesManager(String titl, String table, String col){

		title 		= titl;
		tableName 	= table;
		colName		= col;
	}


	Connection cnn=null;
	ResultSet rs=null;
	
	public void doGet(HttpServletRequest req, HttpServletResponse res)throws IOException, ServletException{

	res.setContentType("text/html; charset=UTF-8");
	StringWriter sWriter = new StringWriter();  
	PrintWriter out = new PrintWriter(sWriter);  	
			
try{		
	int option = Integer.parseInt(req.getParameter("option"));

//Insert categories
	if(option==1){
		GlobalCategoriesMethods gcm = new GlobalCategoriesMethods();
		out.println("<form action=\"/servlet/GlobalCategoriesManager\" method=post>"+
			    gcm.showInsertForm()+
			    "</form>");
	}
//update categories
	else if(option==2){
		String catId = req.getParameter("category");
		
		
	}
//delete categories
	else if(option==3){
		
	}
//display categories
	else if(option==4){
		
	}
//list categories
	else if(option==5){
		
	}
//specific category
	else if(option==6){
		String specificCategory = req.getParameter("category");
	}

	else{}


}catch(Exception e){
	ErrorCheck ec = new ErrorCheck();
	ec.errorMsg("ERROR.GlobalCategoriesManager.java", e);
}
finally  {      
	try {        
		if ( rs  != null ) 	 rs.close();    
		if ( cnn != null )  	cnn.close();  
		
	} catch(SQLException ex) {   
	ErrorCheck ec = new ErrorCheck();	       
	ec.errorMsg("ERROR.GlobalCategoriesManager.java", ex);
	}
}
res.getWriter().print(sWriter.toString());
}

my WEB-INF

<servlet>
        <servlet-name>GlobalCategoriesManager</servlet-name>
        <servlet-class>GlobalCategoriesManager</servlet-class>
   </servlet>  
    

<servlet-mapping>
    	<servlet-name>GlobalCategoriesManager</servlet-name>
        <url-pattern>/servlet/GlobalCategoriesManager</url-pattern>
    </servlet-mapping>

When I ran servlet then its throwing following exception:

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Wrapper cannot find servlet class GlobalCategoriesManager or a class it depends on
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	java.lang.Thread.run(Thread.java:619)
root cause

java.lang.ClassNotFoundException: GlobalCategoriesManager
	org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)
	org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	java.lang.Thread.run(Thread.java:619)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.

Thanks in anticipation

Best regards

[Prajakta Acharya]

The servlet-class element should have fully qualified class name of the servlet.

Also, put a default constructor explicitly since there is a custom constructor in the class.

[Bear Bibeault]

Prajakta Acharya wrote:Also, put a default constructor explicitly since there is a custom constructor in the class.

Why is there a constructor? Servlets should never have constructors.

[Farakh khan]

Hello,

I change WEB-INF as follow:

<servlet>
        <servlet-name>GlobalCategoriesManager</servlet-name>
        <servlet-class>globalcategories.classes.GlobalCategoriesManager</servlet-class>
   </servlet>  
    

<servlet-mapping>
    	<servlet-name>GlobalCategoriesManager</servlet-name>
        <url-pattern>/servlet/GlobalCategoriesManager</url-pattern>
    </servlet-mapping>

and now its giving following exception:

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error instantiating servlet class globalcategories.classes.GlobalCategoriesManager
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	java.lang.Thread.run(Thread.java:619)
root cause

java.lang.InstantiationException: globalcategories.classes.GlobalCategoriesManager
	java.lang.Class.newInstance0(Class.java:340)
	java.lang.Class.newInstance(Class.java:308)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	java.lang.Thread.run(Thread.java:619)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.

Apache Tomcat/6.0.18

I removed constructor and its working fine now

Thanks again

[Farakh khan]

Bear Bibeault wrote:

Prajakta Acharya wrote:Also, put a default constructor explicitly since there is a custom constructor in the class.

Why is there a constructor? Servlets should never have constructors.

You are very right

Thanks for favoring

[Prajakta Acharya]

Oops.....yes, servlet shouldn't have a constructor at first place.
Sorry for that.

Just imagined what will be the next error once a fully qualified class is referred in web.xml.
Container will not be able to instantiate it and wrote that.

But yes, the constructor should not be there.