[ACCEPTED]-Why am I getting a NullPointerException when trying to read a file?-itext

Accepted answer
Score: 20

Sounds like the resource probably doesn't 19 exist with that name.

Are you aware that 18 Class.getResourceAsStream() finds a resource relative to that class's 17 package, whereas ClassLoader.getResourceAsStream() doesn't? You can use a 16 leading forward slash in Class.getResourceAsStream() to mimic this, so 15


is roughly equivalent to


Is this actually a file 14 (i.e. a specific file on the normal file 13 system) that you're trying to load? If so, using 12 FileInputStream would be a better bet. Use Class.getResourceAsStream() if it's a resource 11 bundled in a jar file or in the classpath 10 in some other way; use FileInputStream if it's an arbitrary 9 file which could be anywhere in the file 8 system.

EDIT: Another thing to be careful 7 of, which has caused me problems before 6 now - if this has worked on your dev box 5 which happens to be Windows, and is now 4 failing on a production server which happens 3 to be Unix, check the case of the filename. The 2 fact that different file systems handle 1 case-sensitivity differently can be a pain...

Score: 1

Are you checking to see if the file exists 3 before you pass it to readFilesInBytes()? Note that Class.getResourceAsStream() returns 2 null if the file cannot be found. You probably 1 want to do:

private static byte[] readFilesInBytes(String file) throws IOException {
  File testFile = new File(file);
  if (!testFile.exists()) {
      throw new FileNotFoundException("File " + file + " does not exist");
  return IOUtils.toByteArray(TestConversion.class.getResourceAsStream(file));

or better yet:

private static byte[] readFilesInBytes(String file) throws IOException {
  InputStream stream = TestConversion.class.getResourceAsStream(file);
  if (stream == null) {
      throw new FileNotFoundException("readFilesInBytes: File " + file
                                      + " does not exist");
  return IOUtils.toByteArray(stream);
Score: 0

This class reads a TXT file in the classpath 6 and uses TextConversion to convert to PDF, then 5 save the pdf in the file system.

Here TextConversion 4 code :

package convert.pdf.txt;
//Conversion to PDF from text using iText.
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;

import convert.pdf.ConversionToPDF;
import convert.pdf.ConvertDocumentException;

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Font;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.PdfWriter;

public class TextConversion implements ConversionToPDF {

    public byte[] convertDocument(byte[] documents) throws ConvertDocumentException {
        try {
            return this.convertInternal(documents);
        } catch (DocumentException e) {
            throw new ConvertDocumentException(e);
        } catch (IOException e) {
            throw new ConvertDocumentException(e);

    private byte[] convertInternal(byte[] documents) throws DocumentException, IOException {
        Document document = new Document();

        ByteArrayOutputStream pdfResultBytes = new ByteArrayOutputStream();
        PdfWriter.getInstance(document, pdfResultBytes);


        BufferedReader reader = new BufferedReader( new InputStreamReader( new ByteArrayInputStream(documents) ) );

        String line = "";
        while ((line = reader.readLine()) != null) {
            if ("".equals(line.trim())) {
                line = "\n"; //white line
            Font fonteDefault = new Font(Font.COURIER, 10);
            Paragraph paragraph = new Paragraph(line, fonteDefault);



        return pdfResultBytes.toByteArray();

And here the code to ConversionToPDF 3 :

package convert.pdf;
// Interface implemented by the conversion algorithms.
public interface ConversionToPDF {

    public byte[] convertDocument(byte[] documentToConvert) throws ConvertDocumentException;

I think the problem come from my file system 2 (devbox on windows and server is Unix). I 1 will try to modify my classpath.

Score: 0

This problem may be caused by calling methods 4 on test.txt, which can be a folder shortcut. In 3 other words, you're calling a method on 2 a file that doesn't exist, resulting in 1 a NullPointerException.

More Related questions