Java.lang.illegalargumentexception: not a managed type

An IllegalArgumentException with the message “not a managed type” indicates that the specified class is not recognized as a managed entity by Hibernate or JPA.

To understand this issue, let’s assume you have an application that uses Hibernate or JPA for data persistence. When you define your entities, you annotate them with the @Entity annotation to indicate that they are managed entities. For example:

@Entity
public class Product {
    // entity fields, getters/setters, etc.
}
    

Now, if you encounter the “not a managed type” exception, it usually means that you have not properly annotated your entity class or you have not included it in the list of entities to be managed by Hibernate or JPA.

To resolve this issue, make sure to:

1. Verify that your entity class is annotated with @Entity.
2. Ensure that your entity class is included in the persistence.xml (if using JPA) or hibernate.cfg.xml (if using Hibernate) configuration file. For example:

<persistence-unit name="myPersistenceUnit">
    <class>com.example.Product</class>
</persistence-unit>
        

3. Check that the entity class is scanned by the persistence provider. If you are using JPA, most frameworks automatically scan for annotated classes. However, if you have disabled this feature or have a non-standard configuration, you may need to explicitly define the classes to be scanned. For example, in Spring Boot, you can use the @EntityScan annotation:

@SpringBootApplication
@EntityScan(basePackages = "com.example")
public class MyApplication {
    // application code
}
        

By ensuring that your entity is properly annotated and included in the entity scanning process, you should be able to resolve the “not a managed type” exception.