[PDFBOX-5586] NullPointerException when closing RandomAccessReadMemoryMappedFile more than once

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0 PDFBox
• Fix Version/s: 3.0.0 PDFBox
• Component/s: IO
• Assignee: Andreas Lehmkühler
• Reporter: Andreas Lehmkühler
• Created: 13/Apr/23 06:26
• Updated: 18/Aug/23 05:46
• Resolved: 13/Apr/23 06:29

Description

Matt Bamberger posted an error on users@pdfbox.a.o

I'm using pdfbox 3.0.0-alpha3
When I use a RandomAccessReadMemoryMappedFile to load a PDDocument, I get a NullPointerException when I close it after the PDDocument is closed:

try (RandomAccessReadMemoryMappedFile reader = new RandomAccessReadMemoryMappedFile(file)) {
  try (PDDocument doc = Loader.loadPDF(reader, null, null, null, null)) {
    // ...
  }
}

I found that it's because this.mappedByteBuffer is already null the second time around, so I think you can just wrap in a not-null check:

public void close() throws IOException {
  if (this.fileChannel != null) {
    this.fileChannel.close();
  }

  if (this.mappedByteBuffer != null) { // add this
    Optional.ofNullable(this.unmapper).ifPresent((u) -> {
      u.accept(this.mappedByteBuffer); // exception is thrown in here
    });
    this.mappedByteBuffer = null;
  }
}