Starting MuleSoft runtime version 4.9, MuleSoft has stopped supporting JDK 1.8 for all its newer runtimes. This makes it imperative to upgrade the older versions of all MuleSoft codes to make them JDK17 compliant to ensure the currency of the runtime versions. Some APIs built on older versions of the runtime, i.e., 4.4.0 and older, might need significant changes in the code; the APIs built on newer versions are less susceptible to major code overhauls.

Step-1:

Upgrade Anypoint Studio to Version 7.21

1. Open Anypoint Studio.

2. Go to Help → About Anypoint Studio to check the current version of your studio.

3. Check for Studio Version

4. Download and Install the Latest Version

If you are using an older version, download the latest version of Anypoint Studio 7.21 from the MuleSoft website.

5. Once downloaded, follow the installation instructions for your operating system.

6. Verify Studio Version:

After installation, go to Help → About Anypoint Studio to verify that you’re using version 7.21

Step-2:

1. Configure Anypoint Studio to Use JDK 17

2. Update Studio’s JDK Setting

3. Go to Window → Preferences → Java → Installed JREs.

4. Click Add → Standard VM → Next.

5. Browse to the location of your JDK 17 installation and select the JDK directory.

6. Once added, select it as the default JRE for Studio.

7. Ensure Java 17 is Set as the Default:

8. Make sure that JDK 17 is also selected as the active JDK in Preferences → Java → Compiler. Set the Java Compiler Compliance Level to 17.

Step-3:

Identifying JDK 17 changes and Runtime 4.9

Update Studio’s Maven configuration to point to Maven 3.8 on your local machine.

The built-in JDK can be changed if needed. To verify the currently configured JDK version, run %JAVA_HOME% from the Windows or Linux command line. This will display the active JDK path.

Step-4:

Steps to Upgrade:

1. Take the latest branch
2. Create a new branch out of it as –> runtime-4.9-upgrade

Step-5: Clone the Branch Locally

Step-6:

1. Once you import the project, select the upgrade option and upgrade.

2. After the auto upgrade, open the POM.xml and check the runtime version and mule.maven.plugin.version. If they do not match the following screenshot, make changes manually.

3. Next, right click on the project and traverse to manage dependencies à manage modules.

4. Upgrade all the modules that show up in the list.

NOTE: Please be very careful with any custom connector, like Amazon connectors. Before you upgrade, please compare the existing operations with the operations in the upgraded version. Some operations may change without prior notice and thus break the code.

5. Run the code on Studio
6. Ensure the code startup happens WITHOUT any errors.

7. The code is ready to be checked in and deployed through the pipeline.
8. Before checking in, please validate the changes, make sure no logic code is going to change
9. Commit the changes to the feature branch you created.
10. Check the GitLab to ensure changes reflect

Step-7:

1. Create a merge request with the DEVELOP branch. Validate the merge changes.

2. Merge. This will merge the branch and trigger the pipeline.

3. Once deployment is complete, check the Anypoint Platform Logs. Ensure there are no startup errors.

After saving and applying in the runtime manager while redeploying, we have to upgrade the security policy in Anypoint Manager as shown below:
Then it successfully deployed with version 4.9 in the cloud.

Note: When working with Java 17 in MuleSoft, you may encounter issues with the lookup function, particularly if your project includes outdated or incompatible dependencies. These dependencies may not align with changes introduced in newer Java versions, causing the lookup function to fail at runtime.

Solution: Instead of relying on the lookup function, it’s recommended to use Flow References () for invoking flows. Flow references are more stable and compatible across Java versions and provide better clarity and maintainability within your Mule applications.

Recommended Actions for Java 17 Compatibility:

1. Upgrade Connectors: Ensure all connectors are updated to the latest versions. If you’re using connectors like Lookup, Salesforce, or Database connectors, check for Java 17 compatibility.
2. Test Thoroughly: After upgrading to Java 17, thoroughly test your application to ensure all connectors function as expected.
3. Review Anypoint Studio Logs: If a connector has issues, Anypoint Studio’s logs often give clues as to which part of the connector or its dependencies is causing the problem.
4. Use the Latest Mule Runtime: To ensure better compatibility with Java 17, ensure you are using Mule Runtime 4.4.x or later.

Summary of Key Benefits:

Java 17:

• Long-term support and security updates.
• Enhanced performance, reduced latency, and resource optimization.
• New language features that make code more readable and maintainable.
• Support for cloud-native applications and microservices.
• Improved security and Java 17-specific APIs.

Anypoint Studio 7.21:

• Full compatibility with Java 17.
• Enhanced developer experience with a refined UI and faster deployment processes.
• Improved integration with CloudHub, Mule runtime, and Anypoint Platform.
• Access to the latest Mule runtime features and optimizations.
• Better debugging, monitoring, and CI/CD integration.

Conclusion:

Upgrading to Java 17 and Anypoint Studio 7.21 improves your Mule 4 application development by providing long-term support, security enhancements, better performance, and new features that can simplify development and maintenance. It also ensures that your applications are future-proof and aligned with the latest technologies. This upgrade is essential for staying competitive in the ever-evolving landscape of cloud integration and API management.