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Thread: null pointer exception helpppppppppp

  1. #1
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    Exclamation null pointer exception helpppppppppp

    \\Dear sir plz help im getting null pointer exception
    \\if you want to execute this code createa file testPOIWrite.xls in c:\temp







    import java.io.*;
    import java.util.*;
    import org.apache.poi.hssf.usermodel.HSSFSheet;
    import org.apache.poi.hssf.usermodel.HSSFWorkbook;
    import org.apache.poi.ss.usermodel.Row;
    import org.apache.poi.ss.usermodel.Cell;
    import java.io.FileOutputStream;
    import org.apache.poi.hssf.usermodel.HSSFCell;
    import org.apache.poi.hssf.usermodel.HSSFRow;
    import org.apache.poi.hssf.usermodel.HSSFSheet;
    import org.apache.poi.hssf.usermodel.HSSFWorkbook;

    class bentupdate
    {
    static String [][] excelData;
    static int nop=0,advamt,balamt,amt;
    static String cus="",pl="",typ="",db="",dd="";

    public static void main(String args[])
    {
    Scanner sc=new Scanner(System.in);
    System.out.println("Enter name of customer");
    cus=sc.next();

    System.out.println("Enter place");
    pl=sc.next();

    System.out.println("Enter type ofplant");
    typ=sc.next();

    System.out.println("Enter date of booking in dd/mm/yy");
    db=sc.next();

    System.out.println("Enter date of delivery in dd/mm/yy");
    dd=sc.next();

    System.out.println("Enter no. of plants");
    nop=sc.nextInt();

    System.out.println("Enter amt");
    amt=sc.nextInt();

    System.out.println("Enter advamce amt");
    advamt=sc.nextInt();

    System.out.println("Enter Balance amt");
    balamt=sc.nextInt();

    // --------------------------------------------------------------------------

    try {
    FileInputStream file = new FileInputStream(new File("C:\\temp\\testPOIWrite.xls"));

    HSSFWorkbook workbook = new HSSFWorkbook(file);
    HSSFSheet sheet = workbook.getSheetAt(0);
    Cell cell=null;


    int x=1,y=0;
    for(x=1;x<200;x++)
    {
    cell=sheet.getRow(x).getCell(0);
    if(cell.getCellType() == Cell.CELL_TYPE_BLANK)
    {
    //Update the value of cell
    sheet.getRow(x).getCell(0).setCellValue(x);
    cell = sheet.getRow(x).getCell(0);
    cell.setCellValue(x);
    cell = sheet.getRow(x).getCell(1);
    cell.setCellValue(cus);
    cell = sheet.getRow(x).getCell(2);
    cell.setCellValue(pl);
    cell = sheet.getRow(x).getCell(3);
    cell.setCellValue(typ);
    cell = sheet.getRow(x).getCell(4);
    cell.setCellValue(db);
    cell = sheet.getRow(x).getCell(5);
    cell.setCellValue(nop);
    cell = sheet.getRow(x).getCell(6);
    cell.setCellValue(amt);
    cell = sheet.getRow(x).getCell(7);
    cell.setCellValue(advamt);
    cell = sheet.getRow(x).getCell(8);
    cell.setCellValue(balamt);
    cell = sheet.getRow(x).getCell(9);
    cell.setCellValue(dd);

    FileOutputStream outFile =new FileOutputStream(new File("C:\\temp\\testPOIWrite.xls"));
    workbook.write(outFile);
    outFile.close();
    file.close();



    System.exit(0);
    }
    }



    }
    catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }
    catch (NullPointerException e) {
    e.printStackTrace();
    }

    }
    }

    \\Dear sir plz help im getting null pointer exception
    \\if you want to execute this code createa file testPOIWrite.xls in c:\temp







    import java.io.*;
    import java.util.*;
    import org.apache.poi.hssf.usermodel.HSSFSheet;
    import org.apache.poi.hssf.usermodel.HSSFWorkbook;
    import org.apache.poi.ss.usermodel.Row;
    import org.apache.poi.ss.usermodel.Cell;
    import java.io.FileOutputStream;
    import org.apache.poi.hssf.usermodel.HSSFCell;
    import org.apache.poi.hssf.usermodel.HSSFRow;
    import org.apache.poi.hssf.usermodel.HSSFSheet;
    import org.apache.poi.hssf.usermodel.HSSFWorkbook;

    class bentupdate
    {
    static String [][] excelData;
    static int nop=0,advamt,balamt,amt;
    static String cus="",pl="",typ="",db="",dd="";

    public static void main(String args[])
    {
    Scanner sc=new Scanner(System.in);
    System.out.println("Enter name of customer");
    cus=sc.next();

    System.out.println("Enter place");
    pl=sc.next();

    System.out.println("Enter type ofplant");
    typ=sc.next();

    System.out.println("Enter date of booking in dd/mm/yy");
    db=sc.next();

    System.out.println("Enter date of delivery in dd/mm/yy");
    dd=sc.next();

    System.out.println("Enter no. of plants");
    nop=sc.nextInt();

    System.out.println("Enter amt");
    amt=sc.nextInt();

    System.out.println("Enter advamce amt");
    advamt=sc.nextInt();

    System.out.println("Enter Balance amt");
    balamt=sc.nextInt();

    // --------------------------------------------------------------------------

    try {
    FileInputStream file = new FileInputStream(new File("C:\\temp\\testPOIWrite.xls"));

    HSSFWorkbook workbook = new HSSFWorkbook(file);
    HSSFSheet sheet = workbook.getSheetAt(0);
    Cell cell=null;


    int x=1,y=0;
    for(x=1;x<200;x++)
    {
    cell=sheet.getRow(x).getCell(0);
    if(cell.getCellType() == Cell.CELL_TYPE_BLANK)
    {
    //Update the value of cell
    sheet.getRow(x).getCell(0).setCellValue(x);
    cell = sheet.getRow(x).getCell(0);
    cell.setCellValue(x);
    cell = sheet.getRow(x).getCell(1);
    cell.setCellValue(cus);
    cell = sheet.getRow(x).getCell(2);
    cell.setCellValue(pl);
    cell = sheet.getRow(x).getCell(3);
    cell.setCellValue(typ);
    cell = sheet.getRow(x).getCell(4);
    cell.setCellValue(db);
    cell = sheet.getRow(x).getCell(5);
    cell.setCellValue(nop);
    cell = sheet.getRow(x).getCell(6);
    cell.setCellValue(amt);
    cell = sheet.getRow(x).getCell(7);
    cell.setCellValue(advamt);
    cell = sheet.getRow(x).getCell(8);
    cell.setCellValue(balamt);
    cell = sheet.getRow(x).getCell(9);
    cell.setCellValue(dd);

    FileOutputStream outFile =new FileOutputStream(new File("C:\\temp\\testPOIWrite.xls"));
    workbook.write(outFile);
    outFile.close();
    file.close();



    System.exit(0);
    }
    }



    }
    catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }
    catch (NullPointerException e) {
    e.printStackTrace();
    }

    }
    }
    Last edited by Norm; May 5th, 2013 at 05:58 AM. Reason: Duplicate


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: null pointer exception helpppppppppp

    Please copy the full text of the error message and paste it here. It has important info about the error.

    Please edit your post and wrap your code with code tags:
    [code=java]
    <YOUR CODE HERE>
    [/code]
    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
    Junior Member
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    Default Re: null pointer exception helpppppppppp

    java.lang.NullPointerException
    at bentupdate.main(bentupdate.java:62)
    at __SHELL0.run(__SHELL0.java:6)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at bluej.runtime.ExecServer$3.run(ExecServer.java:725 )
    I am new user and i dont know this site if you still want the code download it from ..first create a excel file in "C:\\temp\\testPOIWrite.xls"
    download the code [URL="http://www.mediafire.com/view/?9gmmh3yy49ub96x"]

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: null pointer exception helpppppppppp

    java.lang.NullPointerException
    at bentupdate.main(bentupdate.java:62)
    There is a variable with a null value on line 62. Look at line 62 in the your source and see what variable is null. Then backtrack in the code to see why that variable does not have a valid value.
    If you can not tell which variable it is, add a println just before line 62 and print out the values of all the variables on that line.
    If you don't understand my answer, don't ignore it, ask a question.

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