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  #1 (permalink)  
Old December 30th, 2006, 04:34 PM
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Default help with nullPointerException tomcat

I have made a catalog using a servlet but when i try to run it i just get this in the browser:

java.lang.NullPointerException
    at coreservlets.Catalog.getItem(Catalog.java:18)
    at coreservlets.CatalogPage.setItems(CatalogPage.java :40)
    at coreservlets.KidsBooksPage.init(KidsBooksPage.java :16)
    at javax.servlet.GenericServlet.init(GenericServlet.j ava:258)
    at org.apache.catalina.core.StandardWrapper.loadServl et(StandardWrapper.java:918)
    at org.apache.catalina.core.StandardWrapper.allocate( StandardWrapper.java:655)
    at org.apache.catalina.servlets.InvokerServlet.serveR equest(InvokerServlet.java:400)
    at org.apache.catalina.servlets.InvokerServlet.doGet( InvokerServlet.java:180)
    at javax.servlet.http.HttpServlet.service(HttpServlet .java:740)
    at javax.servlet.http.HttpServlet.service(HttpServlet .java:853)
    at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:247)
    at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:193)
    at filters.ExampleFilter.doFilter(ExampleFilter.java: 149)
    at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:213)
    at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:193)
    at filters.ExampleFilter.doFilter(ExampleFilter.java: 149)
    at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:213)
    at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:243)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:566)
    at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:472)
    at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:943)
    at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:190)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:566)
    at org.apache.catalina.authenticator.AuthenticatorBas e.invoke(AuthenticatorBase.java:475)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:564)
    at org.apache.catalina.valves.CertificatesValve.invok e(CertificatesValve.java:246)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:564)
    at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:472)
    at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:943)
    at org.apache.catalina.core.StandardContext.invoke(St andardContext.java:2347)
    at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:180)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:566)
    at org.apache.catalina.valves.ErrorDispatcherValve.in voke(ErrorDispatcherValve.java:170)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:564)
    at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:170)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:564)
    at org.apache.catalina.valves.AccessLogValve.invoke(A ccessLogValve.java:468)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:564)
    at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:472)
    at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:943)
    at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:174)
    at org.apache.catalina.core.StandardPipeline.invokeNe xt(StandardPipeline.java:566)
    at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:472)
    at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:943)
    at org.apache.catalina.connector.http.HttpProcessor.p rocess(HttpProcessor.java:1027)
    at org.apache.catalina.connector.http.HttpProcessor.r un(HttpProcessor.java:1125)
    at java.lang.Thread.run(Thread.java:595)
can anyone explain to me what would cause this i think it has something to do with this peice of code:

     for(int i=0; i<items.length; i++) {
          out.println("");
          printitem = items[i];
    if (printitem == null) {
        out.println("" +
                    "Unknown recording ID " +
                    "");
      } else {
           added[i] = items[i];
    out.println( added[i] + "\n" +
       item.gettitle() + "\n" +
           item.getprice() + "\n" +
       item.getdirector() + "\n" +
       item.getcategory() + "\n" +
       item.getduration() + "\n" +
       item.getrating() + "\n" +
       item.getyear() + "\n");

    out.println("\n</BODY></HTML>");
      }
    }

please any help would be excellent i need to get this working soon lol its driving me mad!!!!!! Below is my servlet file

package coreservlets;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

public class Catalog extends HttpServlet {
private static CatalogItem added[];
private static CatalogItem[] items;
CatalogItem item;
CatalogItem details;

public static CatalogItem getItem(int recordingid) {
          CatalogItem item;
          for(int i=0; i<items.length; i++) {
            item = items[i];
            if (recordingid==item.getrecordingid()) {
              return(item);
          }
        }
        return(null);
      }

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();



    Connection conn = null;
    String imageDB;
    String titleDB;
    String directorDB;
    String categoryDB;
    int durationDB;
    String ratingDB;
    String yearDB;
    float priceDB;
    int recordingidDB;




    try{
        Class.forName("com.mysql.jdbc.Driver").newInstance ();
    } catch(Exception e) {
        System.out.println(e);
    }


    try{

        conn = DriverManager.getConnection
        ("jdbc:my sql url goes here");

    }
       catch(SQLException se) {
        System.out.println(se);
    }


    try{

        String selectSQL = "select image_name, title, director, category, duration, rating, year_released, price, recording_id "+
                                       "from video_recordings ";


        Statement stmt = conn.createStatement();
        ResultSet rs1 = stmt.executeQuery(selectSQL);


// Retrieve the results
        while(rs1.next()){

        recordingidDB = rs1.getInt("recording_id");
        imageDB = rs1.getString("image_name");
        titleDB = rs1.getString("title");
        directorDB = rs1.getString("director");
        categoryDB = rs1.getString("category");
        durationDB = rs1.getInt("duration");
        ratingDB = rs1.getString("rating");
        yearDB = rs1.getString("year_released");
        priceDB = rs1.getFloat("price");
        double priceD = priceDB;

          item =
         new CatalogItem
            (recordingidDB,
              titleDB,
              directorDB,
              categoryDB,
               durationDB,
              ratingDB,
                yearDB,
              priceD);


    }

    String title = "Catalog";

    out.println( "<HTML>\n" +
                "<HEAD><TITLE>" + title + "</TITLE></HEAD>\n" +
                "<H1 ALIGN=\"CENTER\">" + title + "</H1>");


        for(int i=0; i<items.length; i++) {
          out.println("");
          details = items[i];
    if (details == null) {
        out.println("
                    sorry an error "
                    );
      } else {
           added[i] = items[i];
    out.println( added[i] + "\n" +
       item.gettitle() + "\n" +
           item.getprice() + "\n" +
       item.getdirector() + "\n" +
       item.getcategory() + "\n" +
       item.getduration() + "\n" +
       item.getrating() + "\n" +
       item.getyear() + "\n");

    out.println("\n</BODY></HTML>");
      }
    }


// Close the stament and database connection
// (must remember to always do this)
        stmt.close();
        conn.close();
    } catch(SQLException se) {
        System.out.println(se);
     }
  }
}

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  #2 (permalink)  
Old March 26th, 2007, 01:52 AM
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Default

Hi,

If you look at the condition part of the for loop in getItem() method, you are calling length on items variable, items might me null check for null value for items variable, i thing thats causing NullPointerException.

for(int i=0; i<items.length; i++) {

Regards,
Rakesh
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