SpringBoot_Lesson1_Sample2

Propmt for the Code Agent (Codex, Gemini Code Assistant or Copilot)

Context:

You are an expert Spring developer. We are now refactoring the previous application to use the core Spring Framework for Dependency Injection.

The goal is to let the Spring IoC container manage the MessageService and inject it into the MainApplication.

Task:

Modify the previous Maven project to use the Spring Framework.

Constraints:

• Java 17

• Use Spring Framework 6.x (spring-context dependency).

• Use annotation-based configuration.

Steps:

1. Update the pom.xml to add the spring-context dependency.

2. Annotate the MessageService class with @Component to make it a Spring bean.

3. Create a configuration class AppConfig.java annotated with @Configuration and @ComponentScan("com.example.demo").

4. Modify MainApplication.java:

   • In the main method, create an AnnotationConfigApplicationContext, passing AppConfig.class to its constructor. This will start the Spring container.

   • Use the context to get the MessageService bean (e.g., context.getBean(MessageService.class)).

   • Print the message from the service to the console.

5. Provide the mvn command to run the refactored application.

Deliverables:

• Updated pom.xml

• src/main/java/com/example/demo/MessageService.java (with @Component)

• src/main/java/com/example/demo/AppConfig.java (new file)

• Updated src/main/java/com/example/demo/MainApplication.java

• The mvn command to execute the application.

Acceptance Criteria (Part 2):

• The project compiles successfully.

• Running the main method prints "Hello, world!" to the console.

• The MainApplication class no longer uses the new keyword to create MessageService. It gets the instance from the Spring ApplicationContext.

• MessageService is marked with the @Component annotation.