Add UserEntity class

src/main/java/com/example/demo/DemoApplication.java

@@ -1,5 +1,6 @@
 package com.example.demo;
 
+import domain.UserEntity;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@@ -9,6 +10,8 @@ public class DemoApplication {
 	public static void main(String[] args) {
 		System.out.println("Start application");
 		SpringApplication.run(DemoApplication.class, args);
+		System.out.println("App running");
+		UserEntity.showUserEntityMessage();
 	}
 
 }

src/main/java/domain/UserEntity.java

@@ -0,0 +1,7 @@
+package domain;
+
+public class UserEntity {
+    public static void showUserEntityMessage() {
+        System.out.println("wiadomość z klasy UserEntity");
+    }
+}