How to Set License for GroupDocs Watermark (Metered) in Java

Protecting intellectual property is a top priority for modern businesses, and watermarks are a proven way to do it. In this tutorial you’ll learn how to set license for GroupDocs.Watermark using a metered approach, so you can apply watermark pdf files while keeping full control over usage. We’ll walk through everything from prerequisites to real‑world usage scenarios, and show you exactly where to use public private keys to activate the license.

Quick Answers

  • What is a metered license? A usage‑based licensing model that tracks each API call.
  • Do I need a license file? No – you activate with public and private keys.
  • Which Java version is required? Java 8 or higher.
  • Can I add watermark pdf documents? Yes, the API supports PDF, DOCX, PPTX, and images.
  • Is this method secure? Yes, keys are transmitted over HTTPS and never stored in plain text.

What is a Metered License and Why Use It?

A metered license lets you pay for what you actually consume, making it ideal for SaaS or micro‑service architectures. It provides document security watermark capabilities without the overhead of managing traditional license files, and you can scale your usage up or down instantly.

Prerequisites

Before you begin, make sure you have:

  1. GroupDocs.Watermark for Java ≥ 24.11 (the latest release).
  2. JDK 8+ installed and JAVA_HOME configured.
  3. Public and private keys obtained from your GroupDocs account (you’ll use them in the code).

Setting Up GroupDocs.Watermark for Java

Installation Information

Integrate GroupDocs.Watermark into your Maven project:

<repositories>
   <repository>
      <id>repository.groupdocs.com</id>
      <name>GroupDocs Repository</name>
      <url>https://releases.groupdocs.com/watermark/java/</url>
   </repository>
</repositories>

<dependencies>
   <dependency>
      <groupId>com.groupdocs</groupId>
      <artifactId>groupdocs-watermark</artifactId>
      <version>24.11</version>
   </dependency>
</dependencies>

Tip: The same repository URL is also used for the direct download option below.

Direct Download

Grab the latest JAR from the official release page: GroupDocs.Watermark for Java releases.

License Acquisition

To unlock premium features you need a temporary or trial license. Sign up on the GroupDocs website and copy the public/private keys they provide.

Basic Initialization

Once the library is on your classpath, you can initialize it:

import com.groupdocs.watermark.License;

public class InitializeWatermark {
    public static void main(String[] args) throws Exception {
        License license = new License();
        // Apply the license using your path to the license file
        license.setLicense("path/to/your/license/file.lic");
    }
}

Why this matters: Even when you use a metered license, initializing the License object ensures the SDK is ready to accept key‑based activation later in the workflow.

Implementation Guide

Setting a Metered License

Step 1: Define the Public and Private Keys

// Step 1: Define the public and private keys for the metered license.
String publicKey = "*****"; // Replace with your actual public key
String privateKey = "*****"; // Replace with your actual private key

These keys use public private keys to securely identify your account.

Step 2: Create an Instance of the Metered Class

// Step 2: Create an instance of Metered class.
Metered metered = new Metered();

The Metered class handles all usage tracking behind the scenes.

Step 3: Set the Metered License Using Provided Keys

// Step 3: Set the metered license using the provided keys.
metered.setMeteredKey(publicKey, privateKey);

After this call the SDK is fully licensed and you can start to add watermark pdf files or create watermarked documents.

Why Use Public/Private Keys Instead of a License File?

  • Security: Keys are never written to disk in plain text.
  • Flexibility: Switch environments (dev, test, prod) without copying files.
  • Scalability: Perfect for cloud‑native deployments where containers are immutable.

Practical Applications

  1. Document Security: Embed a visible or invisible watermark in PDFs to deter unauthorized distribution.
  2. Usage Tracking: Monitor how many documents are processed each month, helping you stay within your metered quota.
  3. CMS Integration: Automatically apply watermark pdf to every uploaded file in a content management system.

Performance Considerations

  • Apply watermark only when needed – avoid processing large batches unnecessarily.
  • Reuse the Metered instance across requests to reduce object creation overhead.
  • Monitor memory when handling high‑resolution images; the SDK provides streaming APIs to keep the footprint low.

Common Issues and Solutions

IssueSolution
Keys are rejectedDouble‑check that there are no extra spaces or line‑breaks in the strings.
License not activatedEnsure you called metered.setMeteredKey(...) before any watermark operation.
Out‑of‑memory errors on big PDFsUse WatermarkOptions.setUseMemoryCache(true) to offload processing to disk.

Frequently Asked Questions

Q: What is a metered license, and why should I use it?
A: A metered license tracks each API call, letting you pay only for actual usage and easily scale your application.

Q: Can I switch between a trial license file and a metered key?
A: Yes. Just call license.setLicense("path/to/file.lic") for the trial, then later replace it with metered.setMeteredKey(...).

Q: What happens if my public or private key is entered incorrectly?
A: The SDK will throw an authentication exception and block access to premium features.

Q: Are there limits on how many watermarks I can add per month?
A: Limits depend on the agreement you have with GroupDocs; check your dashboard for exact quotas.

Q: Does this work with image files as well as PDFs?
A: Absolutely. The same API supports JPEG, PNG, BMP, and other common image formats.

Resources

Last Updated: 2026-01-21
Tested With: GroupDocs.Watermark 24.11 for Java
Author: GroupDocs