근본 원인 (root cause)

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping': Invocation of init method failed; nested exception is java.lang.IllegalStateException: Ambiguous mapping. Cannot map 'sillyController' method
com.luv2code.springdemo.mvc.SillyController#displayTheform()
to { [/showForm]}: There is already 'helloWorldController' bean method
com.luv2code.springdemo.mvc.HelloWorldController#showForm() mapped.

해결방법

@RequestMapping안의 괄호 값이 중복될 때 발생하는 오류였다. 중복 되지 않게 변경해주니 잘 구동됐다