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My class is not a servlet error

I have the following servlet code

public void doPost(HttpServletRequest request, HttpServletResponse response){

    Backup bup = new Backup();
    bup.doBackup();

    response.setContentType("text/html");
    PrintWriter out;
    try {
        out = response.getWriter();

    out.println("You backed up your data - well hopefully");
    out.flush();
    out.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

And the next stack trace

javax.servlet.ServletException: class view.BackupServlet - not a servlet org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102) org.apache.catalina.connector.CoyoteAdapter.service (CoyoteAdapter.java:293) org .apache.coyote.http11.Http11Processor.process (Http11Processor.java:849) org.apache.coyote.http11.Http11Protocol $ Http11ConnectionHandler.process (Http11Protocol.java//83) org.apache.tomcaterutilnd.pointilnet.utilndo.net.utomnder.netututndt.pointil.net.utomnderutut.tomcaterutil.net .run (JIoEndpoint.java:454) java.lang.Thread.run (Thread.java:619)

The main reason

java.lang.ClassCastException: view.BackupServlet javax.servlet.Servlet   org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)   org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)   org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)   org.apache.coyote.http11.Http11Protocol $Http11ConnectionHandler.process(Http11Protocol.java:583)   org.apache.tomcat.util.net.JIoEndpoint $Worker.run(JIoEndpoint.java:454)   java.lang.Thread.run(Thread.java:619)

web.xml -

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-<br>app_2_4.xsd">
<display-name>Backup</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description>BackupServlet</description>
    <display-name>BackupServlet</display-name>
    <servlet-name>BackupServlet</servlet-name><br>
    <servlet-class>view.BackupServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>BackupServlet</servlet-name>
    <url-pattern>/BackupServlet</url-pattern>
  </servlet-mapping>
</web-app>`
+5
3

- , Servlet HttpServlet.

, , servlet.jar - , .

+12

, doPost, javax.servlet.Servlet, javax.servlet.HttpServlet

public class BackupServlet extends HttpServlet {
    public void doPost(HttpServletRequest request,
                       HttpServletResponse response) {
     .
     .
     .
    }
}
+3

Most likely, you have several versions of servlet libraries (.jar files) uploaded by my server. If you use maven / gradle as a build tool, make sure that you change the scope of the servlet library in scope if it is intended to be provided by the server.

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