why i'm getting this error of HTTP Status 500?

Question

I've created a simple JSP page and made a Servlet called UserController.java which is inside the package com.pro3.controller. In jsp page I have a form with get method. When I submit the form it fails with following exception:

HTTP Status 500 - javax.servlet.ServletException: Error instantiating servlet class com.pro3.controller.UserController

--------------------------------------------------------------------------------

type Exception report

message javax.servlet.ServletException: Error instantiating servlet class com.pro3.controller.UserController

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

exception 

org.apache.jasper.JasperException: javax.servlet.ServletException: Error instantiating servlet class com.pro3.controller.UserController
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:502)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:412)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:723)


root cause 

javax.servlet.ServletException: Error instantiating servlet class com.pro3.controller.UserController
    org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:709)
    org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:680)
    org.apache.jsp.index_jsp._jspService(index_jsp.java:62)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:723)


root cause 

java.lang.NullPointerException
    java.util.Properties$LineReader.readLine(Properties.java:418)
    java.util.Properties.load0(Properties.java:337)
    java.util.Properties.load(Properties.java:325)
    com.pro3.util.DbUtil.getConnection(DbUtil.java:26)
    com.pro3.dao.UserDao.<init>(UserDao.java:19)
    com.pro3.controller.UserController.<init>(UserController.java:27)
    sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    java.lang.Class.newInstance0(Class.java:355)
    java.lang.Class.newInstance(Class.java:308)
    org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:709)
    org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:680)
    org.apache.jsp.index_jsp._jspService(index_jsp.java:62)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

Anyone help me out this problem.

public class DbUtil 
{
    public static Connection connection = null;
    
    public static Connection getConnection()
    {
        if(connection!=null)
            return connection;
        else
        {
            try
            {
                Properties prop=new Properties();
                InputStream inputStream=DbUtil.class.getClassLoader().getResourceAsStream("/db.properities");
                prop.load(inputStream);
                
                String driver=prop.getProperty("driver");
                String url=prop.getProperty("url");
                String user=prop.getProperty("user");
                String password=prop.getProperty("password");
                
                Class.forName(driver);
                connection=DriverManager.getConnection(url,user,password);
                
            }catch(ClassNotFoundException e){
                e.printStackTrace();

This is Null Pointer Exception:

public class UserController extends HttpServlet 
{
    private static final long serialVersionUID = 1L;
    private static String INSERT_OR_EDIT="/user.jsp";
    private static String LIST_USER="/listuser.jsp";
    private UserDao dao;
    
    public UserController() 
    {
        super();
        dao = new UserDao();
    }
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        {
            String forward="";
            String action = request.getParameter("action");
            
            if(action.equalsIgnoreCase("delete"))
            {
                int userId=Integer.parseInt(request.getParameter("userid"));
                dao.deleteUser(userId);
                forward=LIST_USER;
                request.setAttribute("users", dao.getAllUsers());
            }
            else if(action.equalsIgnoreCase("edit"))
            {
                forward=INSERT_OR_EDIT;
                int userId=Integer.parseInt(request.getParameter("userid"));
                User user=dao.getUserById(userId);
                request.setAttribute("user", user);
            }
            else if(action.equalsIgnoreCase("listUser"))
            {
                forward=LIST_USER;
                request.setAttribute("users", dao.getAllUsers());
            }
            else
            {
                forward=INSERT_OR_EDIT;
            }
            RequestDispatcher view=request.getRequestDispatcher(forward);
            view.forward(request, response);
        }
        
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        {
        User user=new User();
        user.setFirstName(request.getParameter("firstname"));
        user.setLastName(request.getParameter("lastname"));
       try
       {
           Date dob = new SimpleDateFormat("dd/mm/yyyy").parse(request.getParameter("dob"));
           user.setDob(dob);
       }
       catch(ParseException e)
       {
           e.printStackTrace();
       }
        user.setEmail(request.getParameter("email"));
        String userid=request.getParameter("userid");
        if(user==null||userid.isEmpty())    
        {
            dao.addUser(user);
        }
        else
        {
            user.setUserid(Integer.parseInt(userid));
            dao.updateUser(user);
        }
        RequestDispatcher view=request.getRequestDispatcher(LIST_USER);
        request.setAttribute("users", dao.getAllUsers());
        view.forward(request, response);
     }
}

Pablo Lozano: He found some error, and then ill do it then, now i getting this kind of error.

HTTP Status 500 - java.lang.NullPointerException

-------------------------------------------------------------------------------- type

Exception report message java.lang.NullPointerException

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

exception

org.apache.jasper.JasperException: java.lang.NullPointerException org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:502) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

rootcause

java.lang.NullPointerException

com.pro3.dao.UserDao.getAllUsers(UserDao.java:74) com.pro3.controller.UserController.doGet(UserController.java:51) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) javax.servlet.http.HttpServlet.service(HttpServlet.java:723) org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:709) org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:680) org.apache.jsp.index_jsp._jspService(index_jsp.java:62) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:723) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

score 0 · Answer 1 · edited May 23 '17 at 11:44

0

It says java.lang.NullPointerException, so there is an object, which is not instantiated. I assume you are using java.lang.Propertis#load(InputStream) in your com.pro3.util.DbUtil.getConnection so you are probably instantiating it (if at all) in a wrong way.

So, you can't use getResourceAsStream from your DbUtils.class (I assume, if you only put your ptoperties into the same package, it will work). Please find out how to properly load properties in Servlet.

edited May 23 '17 at 11:44

Community

1
1

answered Jan 31 '14 at 12:23

Alex K.

3,294
4
29
41

First of all please share your `DbUtil.getConnection()` method, so that we can find out how do you create an `InputStream`. – Alex K. Jan 31 '14 at 12:32

score 0 · Accepted Answer · answered Jan 31 '14 at 14:28

0

DbUtil.class.getClassLoader().getResourceAsStream("/db.properities");

Try to write db.properties instead of db.properities

answered Jan 31 '14 at 14:28

Pablo Lozano

10,122
2
38
59

Your are trying to find a properties file, but the name of the file is misspelled – Pablo Lozano Jan 31 '14 at 14:34

why i'm getting this error of HTTP Status 500?

2 Answers2