How to Fix org.hibernate.AnnotationException: No identifier specified for entity in Spring Boot

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Solving the Hibernate Annotation Error: No Identifier Specified for Entity

Understanding the Problem

In the example you're facing, the specific error is tied to the City class which doesn't have the required annotations to identify its primary key.

The Key Ingredients

To understand better, let’s discuss the components involved:

Entity Class: Represents a table in a database.

@ Entity Annotation: Marks a class as a Hibernate entity.

@ Id Annotation: Designates a field as the entity's identifier.

Typical Scenario

From the stack trace provided, we see the following line:

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This message implies that the City entity lacks the necessary identifier setup.

How to Fix the Error

To solve the annotation exception, the missing @ Id annotation needs to be added to the City class. Below are the steps to implement the fix:

Step 1: Locate the Entity Class

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

Step 2: Add the @ Id Annotation

Within the City class, find the field that will serve as the unique identifier. This is usually a field like id.

You need to modify the existing piece of code that defines your id variable as follows:

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

Complete City Class Example

After making the changes, your City class should look like this:

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

Step 3: Validate the Application Properties

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Step 4: Restart Your Application

After implementing the changes, restart your Spring Boot application. This will help Hibernate reassess the entity configurations and should eliminate the error.

Conclusion

By adding the @ Id annotation and defining your primary key, you ensure that Hibernate can uniquely identify each record within the City table. This resolution is crucial for the correct functioning of any entity in your JPA applications. So, be attentive to your entity annotations to maintain an error-free environment as you develop your applications!

Feel free to reach out if you have further questions or encounter new hurdles in your coding journey!