Andreas Lehmkühler

The FDF parser uses the same on demand logic than the PDFParser so that we must not close the input file. The XFDF-stuff doesn't use the PDFBox parser at all....

The parser is based in the lexer/parser principle. The lexer knows the lexical structure of the format and the parser itself uses the lexer to read an interpret the content...

We have to ensure that the resulting pdf isn't (more) corrupt that the origin one if indirect object references are omitted. To remove a reference from a COSArray shouldn't be...

IMHO to synchronize the part of the code in question may have some downsides. It can slow down the processing and in a worst case scenario it might run into...

Done, I've removed the private member fields, so that the class should be thread-safe again, see https://issues.apache.org/jira/browse/PDFBOX-5819

@pcorless thanks for the feedback and the test.

Thanks for the contribution, looks promising at least at a first sight. And yes, please split up the patch im smaller parts so that it is easier to check the...