How to reduce PDF file size programmatically in Java?

Question

Document document = new Document(reader.getPageSizeWithRotation(1));
PdfCopy writer = new PdfCopy(document, new FileOutputStream(outFile));
document.open();
PdfImportedPage page = writer.getImportedPage(reader, ++i);
writer.setFullCompression();
writer.addPage(page);
document.close();
writer.close();

I am using iText to split and merger the PDF, I need your help to reduce (compress) the output PDF size programmatically. Please let me know the steps to achieve the same.

Answer 1

use iText

PdfReader reader = new PdfReader(new FileInputStream("input.pdf"));
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("output.pdf"));
int total = reader.getNumberOfPages() + 1;
for ( int i=1; i<total; i++) {
   reader.setPageContent(i + 1, reader.getPageContent(i + 1));
}
stamper.setFullCompression();
stamper.close();

Answer 2

Also change the PdfCopy to PdfSmartCopy. It will eliminate duplicate streams which have the same hash (md5).