Resolving Spring MVC Jackson Exception on Payara 5 Startup

Описание: Struggling with Spring MVC and Jackson exceptions on Payara 5 startup? Discover easy solutions to resolve class loading issues and Compatibility problems.
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Handling Spring MVC Jackson Exceptions on Payara 5 Startup

When building applications with Spring MVC and deploying them on Payara 5, developers can sometimes encounter exceptions that disrupt the startup process. If you’ve run into a Jackson Exception, you’re not alone. This post explores a common issue related to version compatibility between Jackson libraries, primarily when running on Payara Server.

The Problem Explained

In a typical scenario, your application might depend on certain versions of libraries. However, Payara 5 includes its own versions of these libraries, which can lead to conflicts. Here's a brief overview of the situation:

Environment:

JDK version: Open JDK (jdk-11.0.11+ 9)

Payara: 5.2021.5

Spring version: 5.2.7.RELEASE

Jackson version: 2.9.4

Your application uses Jackson version 2.9.4 while Payara 5.2021.5 is bundled with Jackson version 2.10.2. Notably, there are changes in method signatures between these versions. When the server attempts to start, it throws an exception indicating a type incompatibility.

Key Error Message

Here's the core of the exception that arises during startup:

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This error particularly points to the issue that a required ObjectMapper type is not matching due to the version conflict.

The Solution: Adjusting Class Loading

To resolve this Jackson exception, adjustments in class loading settings can be pivotal. Below are steps you can take to remedy this issue:

1. Understand Class Loading in Payara

Payara has a specific class loading mechanism that can interfere with how applications access libraries. By default, it prioritizes its bundled versions unless configured otherwise.

2. Modify domain.xml

Set a system property in your domain.xml configuration. This property disables the class loading hierarchy, ensuring that your application’s version of Jackson is loaded instead of the bundled one.

Locate your domain.xml file.

Add the following line to the server configuration:

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3. Testing with glassfish-web.xml

If changes to domain.xml alone don’t yield results, you can tweak the glassfish-web.xml or even create a payara-web.xml. This is particularly useful for applications wanting to adjust how classes are loaded locally.

4. DispatcherServlet Configuration

Additionally, configure your web.xml to include the JSON feature for Jersey along with an init parameter for your DispatcherServlet. Here’s an example configuration:

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Conclusion

Dealing with Jackson exceptions on Payara startup can be frustrating, but correctly managing class loading can simplify the process and get your application running smoothly. Remember to ensure that method signatures and library versions are compatible. By implementing the solutions outlined above, you can resolve these startup issues effectively. If you continue to experience problems, consider upgrading to a more recent version of Jackson for compatibility, or consult the specifc documentation provided for Payara and Spring MVC for further options.

Now you should be ready to tackle this common issue confidently! Happy coding!