Resolving Spring Error: Not a managed type: class with Multiple Data Sources

Discover how to troubleshoot and resolve the Spring error message `Not a managed type: class` when working with multiple data sources in your Spring application.
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Troubleshooting the Spring Error: Not a managed type: class

When developing Spring applications that utilize multiple data sources, encountering errors is a common challenge. One such issue is receiving the cryptic error message: Not a managed type: class. This error can prevent your application from starting, leaving you puzzled about the configuration settings that are causing the problem. In this guide, we will break down this issue and outline the necessary steps to resolve it effectively.

Understanding the Problem

Imagine you're working on a Spring application that integrates three different data sources. You might have set up model classes, repositories, and the necessary configurations for each data source. However, suddenly, when you attempt to start your application, you’re met with the following error:

[[See Video to Reveal this Text or Code Snippet]]

This error typically indicates that Spring's entity management system does not recognize the specified class Transacao as an entity, often caused by misconfiguration in repository or entity management settings.

The Structure of Your Application

From the context provided, we can see the following components involved:

Each of these classes plays a significant role in ensuring that your application recognizes and interacts with the entities and relational databases you are using.

Solution: Adding entityManagerFactoryRef

To resolve the issue, the last piece of the puzzle is to ensure that the @ EnableJpaRepositories annotation is configured properly. This annotation tells Spring Data JPA about the repositories and the associated EntityManagerFactory. If you have multiple data sources, you need to specify which EntityManagerFactory to use among the different configurations.

Here is what you need to do:

Step 1: Update Your Configuration Class

[[See Video to Reveal this Text or Code Snippet]]

Why This Works

By including entityManagerFactoryRef, you are explicitly instructing Spring to use the gpiEntityManagerFactory for the repositories in the specified package. This change informs Spring that the Transacao entity belongs to this configuration, resolving the Not a managed type error.

Step 2: Validate Your Application Configuration

After making the changes, ensure that:

You have correctly annotated your model class Transacao with @ Entity and identified any necessary dependencies.

The repository interface correctly extends a base repository that is compatible with JPA.

Step 3: Restart Your Application

Once you have made these changes, restart your application. You should no longer see the error message, and the application should start correctly.

Conclusion

Working with multiple data sources in Spring can be tricky due to the various configurations involved. The Not a managed type: class error is just one of many hurdles you might face. By carefully adjusting your configuration annotations and ensuring proper entity management, you can solve this problem and continue building robust applications with Spring.

If you have any further questions or run into other issues, don't hesitate to reach out or consul