Use of XSSFWorkbook Sheet interface results in Java Null Pointer exception

Question

I am trying to use the XSSFWorkbook from org.apache.poi.ss.usermodel to read an Excel file. For some reason I am getting a Null Pointer exception when I try to pull data from one of the Sheet methods. I am very new to Java programming, and it may be something very fundamental.

import org.apache.poi.ss.usermodel.*;
public class ReadFile {

public static void main(String[] args) throws InterruptedException, IOException {

    File f = new File("C:/Users/munish/Documents/Training/Selenium/sample.xlsx");
    FileInputStream file = new FileInputStream(f);
    XSSFWorkbook workbook = new XSSFWorkbook(file);
    Sheet sheet = workbook.getSheetAt(0);

    int rowsCount = sheet.getPhysicalNumberOfRows();
    System.out.println("Total number of rows: " + (rowsCount + 1));
    for (int i = 0; i <= rowsCount; i++) {
        Row row = sheet.getRow(i);
        int colCounts = row.getPhysicalNumberOfCells();
        System.out.println("Total number of Cols: " + colCounts);
        for (int j = 0; j < colCounts; j++) {
            Cell cell = row.getCell(j);
            System.out.println("[" + i + "," + j + "]=" + cell.getStringCellValue());
        }
    }

Where is the NPE? Highlighting the line on which it throws would help too. — Pedantic, Feb 20 '14 at 20:19
The Null Pointer Exception is occurring at the 'int rowsCount...' line — user3334428, Feb 20 '14 at 20:36
So that means `workbook.getSheetAt(0)` is returning null. Any idea why? — Pedantic, Feb 20 '14 at 20:37
I verified the file location and the file itself - the first tab (index 0) has all the data. So I don't understand why i'm getting the error. — user3334428, Feb 20 '14 at 20:42

Jake Haller-Roby · Answer 1 · 2016-01-27T17:55:18.077

-1

Your for loop should be:

for (int i = 0; i < rowsCount; i++)

not

for (int i = 0; i <= rowsCount; i++)

edited Jan 27 '16 at 17:55

answered Feb 20 '14 at 20:17

Jake Haller-Roby

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Thanks. I don't think there is a spelling issue here; in any case, the null pointer exception is thrown 2 lines above this, so we are not even getting to this line. – user3334428 Feb 20 '14 at 23:25
Where do you see `rowsCoutn` in the question above? – TylerH Jan 26 '16 at 16:12
1

That was a typo on my part. My answer was meant to be about < vs <= – Jake Haller-Roby Jan 27 '16 at 17:54

Use of XSSFWorkbook Sheet interface results in Java Null Pointer exception

1 Answers1