java.lang.ClassCastException: class my.package.CustomJwtProfile  cannot be cast to class my.package.CustomJwtProfile  (my.package.CustomJwtProfile  is in unnamed module of loader play.runsupport.DelegatedResourcesClassLoader @10d471bd

The error message you’re encountering is indicating a ClassCastException where an object of the same class my.package.CustomJwtProfile is being cast to itself, and it’s detecting them as being in different unnamed modules within different class loaders. This situation is uncommon and might indicate a subtle issue in your application’s class loading or runtime environment.

The error message itself is somewhat unusual, as it seems to be indicating that there’s a class casting problem within the same class and package. Here are a few steps you can take to troubleshoot and potentially resolve this issue:

1. Review Code for Cast Statements: Examine your codebase to identify any explicit cast statements involving the CustomJwtProfile class. Ensure that the casting logic is correct and that the object you’re attempting to cast is of the expected type.
2. Inspect Classpath and Dependencies: Double-check your project’s classpath and dependencies. Ensure that there is no duplication or naming conflicts with the CustomJwtProfile class, especially in different versions.
3. Check for Multiple Class Loaders: The error message mentions different unnamed modules within different class loaders. Investigate whether your application is using multiple class loaders for some reason. This could happen in complex environments like application servers or if you’re using custom class loader configurations.
4. Review Custom Class Loader Code: If you’re using custom class loaders, review the code responsible for loading classes. Ensure that the class loader isn’t behaving unexpectedly and inadvertently loading classes in unexpected ways.
5. Modular Environment Considerations: If you’re working in a modular environment (Java 9 and later), consider how modules and class loaders interact. Make sure your classes are defined in appropriate modules and that class visibility is set correctly.
6. Check Runtime Environment: If you’re using a framework like Play Framework, ensure that your runtime environment is set up correctly. Look for any configuration issues that might lead to multiple class loaders or unexpected behavior.
7. Debugging and Logging: Enable debugging and verbose class loading options if available. This might help you trace how the classes are being loaded and provide more insight into the issue.
8. Library and Framework Versions: Ensure that the versions of any libraries and frameworks you’re using are compatible and not causing unexpected class conflicts.
9. Check for Coding Errors: Make sure there are no typos or mistakes in your code. Sometimes, subtle errors can lead to unexpected behaviors.
10. Community and Documentation: If you’re using a specific framework or library, consult their documentation and community forums. Others might have encountered similar issues and could provide insights.
11. Isolate the Issue: Try to isolate the problematic code or scenario that triggers this error. This can help you narrow down the potential causes.

Without more context, it’s challenging to pinpoint the exact cause of this issue. If you’re still unable to resolve the problem after trying these steps, providing more information about your application’s structure, how you’re using the CustomJwtProfile class, and any relevant code snippets could help in providing more specific assistance.