My First servlet error-HTTP Status 500

Question

Recently Installed apache-tomcat-5.5.27 ,I followed one documentation when i googled for a while like is here [http://linux-sxs.org/internet_serving/c292.html]
when i try to access from web-browser ,it came up with errors like
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 allocating a servlet instance
     org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
     org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
     org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
     org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
     org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
     org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
     org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
     java.lang.Thread.run(Thread.java:595)
root cause
java.lang.UnsupportedClassVersionError: Bad version number in .class file
     java.lang.ClassLoader.defineClass1(Native Method)
     java.lang.ClassLoader.defineClass(ClassLoader.java:620)
     java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
     org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1876)
     org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:889)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1353)
     org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1232)
     org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
     org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
     org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
     org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
     org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
     org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
     org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
     java.lang.Thread.run(Thread.java:595)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.27 logs.Here is the directory structure
#/opt/apache-tomcat-5.5.27/webapps/MyFirst
#/opt/apache-tomcat-5.5.27/webapps/MyFirst/WEB-INF
#/opt/apache-tomcat-5.5.27/webapps/MyFirst/WEB-INF/classes
#/opt/apache-tomcat-5.5.27/webapps/MyFirst/WEB-INF/libI placed web.xml file in WEB-INF directory and HelloWorld.class in WEB-INF/classes and MyFirst.xml in /opt/apache-tomcat-5.5.27/conf/Catalina/localhost/
the files typically contains
web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<servlet>
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/HelloWorld</url-pattern>
</servlet-mapping>
</web-app>
HelloWorld.java
// Filename : HelloWorld.java                                                                                                                               
// Description : This servlet merely says hello!                                                                                                            
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloWorld extends HttpServlet {
    public void doGet ( HttpServletRequest request, HttpServletResponse response )
        throws ServletException, IOException    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<html>");
        out.println("<head><title>Hello, Cruel World!</title></head>");
        out.println("<body>");
        out.println("<h1>Hello, Cruel World !</h1>");
        out.println("This is my first servlet.");
        out.println("</body>");
    }// end doGet                                                                                                                                           
}///:~
MyFirst.xml
<!-- MyFirst Context -->
<Context path="/MyFirst" docBase="MyFirst" debug="0" reloadable="true"/>anybody have idea about this error...

Answer 1

miriyalasrinivas wrote:
java.lang.UnsupportedClassVersionError: Bad version number in .class fileThe class is compiled with a JDK version which is newer than the JRE version used to run the class. To solve this, just clean up your Java environment and align the versions. You can get version information of the Java compiler using javac -version and of the Java runtime using java -version.
That said, this problem is actually not related to servlets. You didn't get a root exception of javax.servlet package. You just got a root exception of java.lang package, which basically makes it a Java SE problem. Questions related to those actually belongs in the 'New to Java' forum.