How to Flatten PDF File in Java

This article will discuss how you can flatten a PDF document, PDF form, and PDF form field using a state-of-the-art PDF library for Java named IronPDF for Java. This process essentially locks the content into place, preventing any further changes or edits to be made to the PDF document.

1. IronPDF for Java

IronPDF for Java is a powerful library that enables developers to work with PDF documents in their Java applications. With IronPDF, developers can easily create, manipulate, and convert PDF files programmatically, saving valuable time and effort.

This library provides a range of features, including the ability to add images, text, and annotations to PDF documents, merge multiple PDFs into a single PDF file, extract content from PDFs, and even convert HTML to PDF.

IronPDF is designed to be user-friendly, with intuitive APIs that make it easy to integrate PDF functionality into existing Java applications. It is also highly customizable, allowing developers to fine-tune the appearance and behavior of their PDF documents to meet specific requirements. Whether you're building a web application, a desktop application, or a mobile app, IronPDF for Java can simplify your PDF-related development tasks and help you deliver high-quality PDF documents to your users.

2. Prerequisites

In order to flatten a PDF using IronPDF, there are certain prerequisites that need to be met. These prerequisites include:

1. Java must be installed on your system, and its path must be set in the environment variables. If you haven't installed Java yet, you can download and install it from the official Java download page.
2. An Integrated Development Environment (IDE) such as Eclipse or IntelliJ IDEA is required to write and execute your code.
3. Maven, a build automation tool, should be integrated with your IDE to manage dependencies and build the project. If you're not familiar with Maven or need help integrating it with your IDE, you can refer to the Maven Installation Guide for guidance.

Once these prerequisites are met, you can proceed with setting up your project and using IronPDF to load and flatten PDF files in your Java application.

3. IronPDF for Java Installation

To get started, open JetBrains IntelliJ IDEA and create a new Maven project.

Create a new Maven project

Upon starting a new project in JetBrains IntelliJ IDEA, a prompt will appear in a new window, asking for the project's name. After entering a suitable name, you may proceed by clicking the "Finish" button.

Naming the project

Once you have clicked the "Finish" button, a new project will be opened in JetBrains IntelliJ IDEA, and you will be presented with the pom.xml file. This file will be used to add dependencies required for the Maven project.

The pom.xml file

Add the relevant dependencies for IronPDF in the pom.xml file. Adding these dependencies will ensure that all the necessary libraries and packages are available for the project to run smoothly. Unfortunately, the dependencies are not explicitly listed in this guide, but ensure that you include IronPDF's Maven repository.

<!-- Example of dependencies to add -->
<dependency>
    <groupId>com.ironsoftware</groupId>
    <artifactId>ironpdf</artifactId>
    <version>YOUR_IRONPDF_VERSION</version>
</dependency>

<!-- Example of dependencies to add -->
<dependency>
    <groupId>com.ironsoftware</groupId>
    <artifactId>ironpdf</artifactId>
    <version>YOUR_IRONPDF_VERSION</version>
</dependency>

After you have successfully added the above dependencies to the pom.xml file, click on the refresh icon that appears in the top right corner of the file to install dependencies.

Install dependencies from the pom.xml file

This process should only take a few minutes, depending on the speed of your internet connection.

4. Flatten PDF Document Using IronPDF

IronPDF can be used to flatten a PDF document, which means that all interactive form fields and annotations will be merged into the document itself. This process makes it impossible to edit or change the content of the fields or annotations.

To flatten a PDF document using IronPDF, you can use the following sample code:

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;
import java.nio.file.Paths;

public class Main {
    public static void main(String[] args) throws IOException {
        // Load the PDF document from a file
        PdfDocument pdfDoc = PdfDocument.fromFile(Paths.get("business plan.pdf"));

        // Flatten all form fields and annotations in the PDF
        pdfDoc.getForm().flatten();

        // Save the flattened PDF document
        pdfDoc.saveAs("output.pdf");
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;
import java.nio.file.Paths;

public class Main {
    public static void main(String[] args) throws IOException {
        // Load the PDF document from a file
        PdfDocument pdfDoc = PdfDocument.fromFile(Paths.get("business plan.pdf"));

        // Flatten all form fields and annotations in the PDF
        pdfDoc.getForm().flatten();

        // Save the flattened PDF document
        pdfDoc.saveAs("output.pdf");
    }
}

Using the above sample code, you can flatten any input document and form fields into static documents. Flattened documents cannot be edited, as the fields and annotations become part of the page content.

The output PDF file

4.1. Flatten PDF directly from URL

You can also directly perform Flatten PDF form fields using IronPDF for Java by providing the URL of a web page or an online form. The flattening process converts the form into a static document, disabling any interactive elements or links.

Input Form Fields

The sample Google Forms

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class Main {
    public static void main(String[] args) throws IOException {
        // Render the PDF directly from a URL
        PdfDocument pdfDoc = PdfDocument.renderUrlAsPdf("https://docs.google.com/forms/d/e/1FAIpQLSeI8_vYyaJgM7SJM4Y9AWfLq-tglWZh6yt7bEXEOJr_L-hV1A/viewform?formkey=dGx0b1ZrTnoyZDgtYXItMWVBdVlQQWc6MQ");

        // Flatten form fields and annotations in the PDF
        pdfDoc.getForm().flatten();

        // Save the flattened PDF document
        pdfDoc.saveAs("output.pdf");
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class Main {
    public static void main(String[] args) throws IOException {
        // Render the PDF directly from a URL
        PdfDocument pdfDoc = PdfDocument.renderUrlAsPdf("https://docs.google.com/forms/d/e/1FAIpQLSeI8_vYyaJgM7SJM4Y9AWfLq-tglWZh6yt7bEXEOJr_L-hV1A/viewform?formkey=dGx0b1ZrTnoyZDgtYXItMWVBdVlQQWc6MQ");

        // Flatten form fields and annotations in the PDF
        pdfDoc.getForm().flatten();

        // Save the flattened PDF document
        pdfDoc.saveAs("output.pdf");
    }
}

The above code will make the form static, making it easier to use as a template for future references.

The output PDF file from the Google Forms website

5. Conclusion

PDF Form-flattening, Flattened PDF file can be an essential step to preserve the layout and formatting of a document, prevent unauthorized modifications, and make it easier to share and display across different platforms. IronPDF for Java is a powerful library that simplifies PDF-related development tasks, allowing developers to create, manipulate, and convert PDF files programmatically. With its intuitive APIs and customization options, developers can fine-tune the appearance and behavior of their PDF documents to meet specific requirements. By following the steps outlined in this article, developers can easily flatten PDF documents using IronPDF for Java, making their documents static and uneditable.

For more tutorials and code examples please visit this Java HTML to PDF samples page. For more coded examples on URL to PDF document please refer to this URL to PDF Conversion Tutorial.

IronPDF for Java is available for free for development purposes, but a license is required for commercial use. However, you can get a free 30-day trial license to try out IronPDF. For more information on licensing, please visit the IronPDF for Java Licensing Information.