Nullpointer exception with empty file name in ZipParameters

[pdenooijer]

Since this change from version 2.9.0 tot 2.9.1 the file name could still be null leading to a null pointer exception.

The validation is done in the FileHeaderFactory, but this is called from the initializeAndWriteFileHeader. As this is now after the directory check, this will never trigger:

  private String validateAndGetFileName(String fileNameInZip) throws ZipException {
    if (!Zip4jUtil.isStringNotNullAndNotEmpty(fileNameInZip)) {
      throw new ZipException("fileNameInZip is null or empty");
    } else {
      return fileNameInZip;
    }
  }

Problematic code, 2e line is the problem when file name is null:

ZipParameters clonedZipParameters = new ZipParameters(zipParameters);
if (isZipEntryDirectory(zipParameters.getFileNameInZip())) {
  clonedZipParameters.setWriteExtendedLocalFileHeader(false);
  clonedZipParameters.setCompressionMethod(CompressionMethod.STORE);
  clonedZipParameters.setEncryptFiles(false);
}
initializeAndWriteFileHeader(clonedZipParameters);

There are multiple solutions to solve this. Moving the validation to an earlier point or making sure there is no null pointer exception by checking if it's not null.

[srikanth-lingala]

Thanks for the elaborate writeup @pdenooijer. I will fix it.

[srikanth-lingala]

Fixed in v2.10.0 released today