package com.handicraft.admin.controller;

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

@RestController
public class TestController {

    @RequestMapping("/test") //localhost:8080/test
    public String test(){
        return "hello sangwoong";
    }
}

package com.handicraft.admin.controller;

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

@RestController
public class TestController {

    @RequestMapping("/test") //localhost:8080/test
    public String test(){
        return "hello";
    }
}

Update TestController.java