Create a new blank PDF document in Java

To create a new document as a blank PDF.

// use the empty constructor to create a blank PDF
PDFDoc doc = new PDFDoc();

// optionally perform some document processing using read write operations 
// found under 'Editing Page Content' or 'Page Manipulation'

// save the document to the filesystem
doc.save(output_filename, SDFDoc.SaveOptions.LINEARIZED, null);

// optionally save the document to a memory buffer
byte[] buf = doc.save(SDFDoc.SaveMode.LINEARIZED, null);

Read & write a PDF file from/to memory buffer
Full source code which illustrates how to read/write a PDF document from/to memory buffer. This is useful for applications that work with dynamic PDF documents that don't need to be saved/read from a disk.