In this how-to topic, we will show you how to sign a PDF document with a digital signature using Java. We will use one of the popular Signature library for signing PDF with a digital signature in Java. You do not need any additional software for the implementation of this feature and can develop the functionality with a few API calls and two-three lines of code.

Steps to Sign PDF with Digital Signature using Java

1. Setup GroupDocs.Signature for Java from the Maven repository in the Java project
2. Add necessary classes for the implementation of digital signature in PDF using Java
3. Create an instance of the Signature class and pass the source PDF to its constructor
4. Create an object of the DigitalSignOptions class and pass the required certificate file and its password to the constructor
5. Call the Sign method of the Signature class, pass the output PDF file name and DigitalSignOptions to it

Digital signature implementation in Java can be easily achieved with help of the above step-by-step instructions. We will initiate the process of signing PDF with a digital signature by installing the required library and adding a reference to the necessary classes. A signature class will be used to load the source PDF document and DigitalSignOptions class will be used to load the certificate and for defining the properties for the digital signature position. Finally, the signed PDF document will be saved to the disk by using the Sign method of the Signature class.

Code to Sign PDF with Digital Signature using Java

We have created a digital signature example in Java to demonstrate the implementation of the feature. We have also defined various properties for the digital signature including background image, left position, the top position, page number, and many others. Moreover, you can provide source documents such as DOCS, XLSX, PPSM, TSV, PPTX, and many more to eSign the with a digital signature.

We have written extensive instructions and a Java program to add digital signature into pdf file in this post. In a recent article, we discussed how to use Java to sign PDF with QR-Code Signatures, see How to Sign PDF with QR Code Signature using Java.