Here is a sample code to add text to a PDF document content using Qoppa’s Java PDF Library, jPDFProcess.

import java.awt.Color;
import java.awt.Font;
import com.qoppa.pdfProcess.PDFDocument;
import com.qoppa.pdfProcess.PDFGraphics;
import com.qoppa.pdfProcess.PDFPage;
public class AddText
    public static void main (String [] args)
            // load PDF document
            PDFDocument pdfDoc = new PDFDocument ("C:\\myfolder\\input.pdf", null);
            // draw text content into a PDF
            PDFPage page = pdfDoc.getPage(0);
            // get Helvetica font size 16
            Font helveticaFont = PDFGraphics.HELVETICA.deriveFont(16f);            
            // draw text on the page 
            page.drawText("hello!", helveticaFont, Color.BLUE, 494, 14, null);
            // save the updated PDF document
            pdfDoc.saveDocument ("C:\\myfolder\\output.pdf");
        catch (Throwable t)