What it is
iText and Apache PDFBox are Java libraries for creating, manipulating, and reading PDF documents. They allow developers to generate dynamic PDFs, extract content, fill forms, merge or split documents, and manage metadata programmatically.
iText and PDFBox provide APIs to create new PDFs, read existing documents, manipulate pages, extract text and metadata, encrypt/decrypt files, and fill PDF forms. iText has a commercial-friendly license for advanced features, while PDFBox is fully open-source under Apache License.
Installation
iText:
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itext7-core</artifactId>
<version>7.2.5</version>
</dependency>
PDFBox:
<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>pdfbox</artifactId>
<version>3.0.0</version>
</dependency>Getting started
The smallest useful thing you can do with it, and what each part means.
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Paragraph;
PdfWriter writer = new PdfWriter("example.pdf");
PdfDocument pdf = new PdfDocument(writer);
Document document = new Document(pdf);
document.add(new Paragraph("Hello, iText PDF!"));
document.close();import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import java.io.File;
PDDocument document = PDDocument.load(new File("example.pdf"));
String text = new PDFTextStripper().getText(document);
System.out.println(text);
document.close();Advanced usage
Where the library earns its place over a simpler alternative.
import org.apache.pdfbox.multipdf.PDFMergerUtility;
PDFMergerUtility merger = new PDFMergerUtility();
merger.addSource("file1.pdf");
merger.addSource("file2.pdf");
merger.setDestinationFileName("merged.pdf");
merger.mergeDocuments(null);import com.itextpdf.layout.element.Image;
import com.itextpdf.io.image.ImageDataFactory;
Image img = new Image(ImageDataFactory.create("logo.png"));
document.add(img);import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
PDAcroForm form = document.getDocumentCatalog().getAcroForm();
form.getField("name").setValue("John Doe");
document.save("filled_form.pdf");pdf.protect(new StandardEncryption(EncryptionConstants.ENCRYPTION_AES_128, "userpass", "ownerpass"));Errors and fixes
The failures you are most likely to hit, and what actually resolves them.
- IOException
- Occurs when the PDF file cannot be read or written. Ensure the file exists and has proper permissions.
- COSVisitorException (iText)
- Thrown during PDF writing errors. Verify document structure and content.
- IllegalArgumentException: page number out of range
- Ensure you access existing pages correctly in a PDF when manipulating or extracting content.
Best practices
- Always close PDDocument or Document objects to release resources.
- Use streaming APIs for large PDFs to avoid memory issues.
- Validate PDF inputs when extracting text or filling forms.
- Consider licensing for iText if using advanced features in commercial applications.
- Use PDFBox for fully open-source projects and simpler PDF manipulation tasks.
Background
Why it exists, and what it was reacting to.
With the increasing use of PDF for reports, invoices, and legal documents, Java developers needed robust libraries to handle PDFs. iText, initially released in 2000, and PDFBox, an Apache project, provide comprehensive APIs to work with PDF files without relying on external applications. They are widely used in enterprise systems for automated PDF generation and processing.