Add startup message for Spring (#8782)

frameworks/Java/spring/src/main/java/hello/App.java

@@ -7,8 +7,10 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
+import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Profile;
+import org.springframework.context.event.EventListener;
 
 import com.zaxxer.hikari.HikariDataSource;
 
@@ -19,6 +21,11 @@ public class App {
 		SpringApplication.run(App.class, args);
 	}
 
+	@EventListener(ApplicationReadyEvent.class)
+    public void runAfterStartup() {
+        System.out.println("Application is ready");
+    }
+
 	@Bean
 	@Profile({ "jdbc", "jpa" })
 	public DataSource datasource(DataSourceProperties dataSourceProperties) {