I am trying to instantiate my servlet but I am getting this 500 Status Error. I have read other posts but none of the proposed solutions seem to apply to my error.
My SampServlet Class
package com.example;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;
@WebServlet(name = "SampServlet", value = "/SampServlet")
public class SampServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//define that we want to send HTML to our browser
response.setContentType("text/html");
// create our PrintWriter that allows us to write out text as well as write HTML to the screen
PrintWriter out = response.getWriter();
try {
out.println("<h3>Testing Servlets</h3>");
}
finally {
out.close();
}
}
}
my web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>SampServlet</servlet-name>
<servlet-class>com.example.SampServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SampServlet</servlet-name>
<url-pattern>/SampServlet</url-pattern>
</servlet-mapping>
</web-app>
Project Structure enter image description here
the error I'm getting when I go to http://localhost:8080/SampServlet
Message Error instantiating servlet class [com.example.SampServlet]
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
jakarta.servlet.ServletException: Error instantiating servlet class [com.example.SampServlet]
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:356)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:867)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1716)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:833)
Root Cause
java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet
java.base/java.lang.ClassLoader.defineClass1(Native Method)
java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1013)
java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2527)
org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:877)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1413)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1257)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:356)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:867)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1716)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:833)
Root Cause
java.lang.ClassNotFoundException: javax.servlet.http.HttpServlet
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1449)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1257)
java.base/java.lang.ClassLoader.defineClass1(Native Method)
java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1013)
java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2527)
org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:877)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1413)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1257)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:356)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:867)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1716)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.base/java.lang.Thread.run(Thread.java:833)
Note The full stack trace of the root cause is available in the server logs.
CodePudding user response:
Tomcat 10.0 and above use the new Jakarta EE packages for code. This means, for example, that javax.servlet.http.HttpServlet
is now jakarta.servlet.http.HttpServlet
. The change started in version 9 of the EE spec thanks to Oracle and their hostility towards the development community.
Your code should start instead with something like:
import jakarta.servlet.*;
import jakarta.servlet.http.*;
import jakarta.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;
@WebServlet(name = "SampServlet", value = "/SampServlet")
public class SampServlet extends HttpServlet {
to use the new specs. Tomcat also has an open source tool that can convert a larger code base from the EE 8 to EE 9 spec.