done

initial/src/main/java/hello/Application.java

 
 import java.util.Arrays;
 
+import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
 
 @SpringBootApplication
 public class Application {
-    
+
     public static void main(String[] args) {
-        ApplicationContext ctx = SpringApplication.run(Application.class, args);
-        
-        System.out.println("Let's inspect the beans provided by Spring Boot:");
-        
-        String[] beanNames = ctx.getBeanDefinitionNames();
-        Arrays.sort(beanNames);
-        for (String beanName : beanNames) {
-            System.out.println(beanName);
-        }
+        SpringApplication.run(Application.class, args);
+    }
+
+    @Bean//It retrieves all the beans
+    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
+        return args -> {
+
+            System.out.println("Let's inspect the beans provided by Spring Boot:");
+
+            String[] beanNames = ctx.getBeanDefinitionNames();
+            Arrays.sort(beanNames);
+            for (String beanName : beanNames) {
+                System.out.println(beanName);
+            }
+
+        };
     }
 
 }

initial/src/main/java/hello/HelloController.java

 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.bind.annotation.RequestMapping;
 
-@RestController
+@RestController//meaning it's ready for use by Spring MVC to handle web requests.
 public class HelloController {
     
-    @RequestMapping("/")
-    public String index() {
+    @RequestMapping("/greeting")//to invoke index method
+    public String index()
+    {
         return "Greetings from Spring Boot!";
     }