Spring Boot Problem because of LSP (failed to refresh live data from process ...)

I just began to use spring boot. My new created project doesn´t work succesfully. I want to run the spring boot app with "run as Spring Boot App" but I´ve got the same error as @Vinay Vaishnav. I´ve tried everything covered in the replies.

My first error was: Failed to refresh live data from process ...

LSP ERROR Before Changes

After that I included following dependency to the pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Because of the added dependency the error is gone but then i´ve got 404

WhiteLabel Error

I also added the livereload devtools in the applicationProperties. It doesn´t matter if this line is added or not.

That´s my code for now:

AppConfiguration.java:

package com.example.demo;

import org.springframework.web.bind.annotation.RequestMapping;

public class AppConfiguration {

    @RequestMapping("/hello") 
    public String hello() {
        return  "Hello World";
    }
}

applicationProperties:

spring.devtools.livereload.enabled=true
server.port=8081

HelloWorldApplication.java:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RestController;


@RestController
@SpringBootApplication
public class HelloWorldApplication {

    public static void main(String[] args) {
        SpringApplication.run(HelloWorldApplication.class, args);
    }
}

My versions:

• Apache Maven 3.6.3
• Spring Boot 2.2.6
• JDK 13.0.2