[Error] The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path

javax.servlet.http.HttpServlet이 java 빌드 경로에 없다

해결방안

project 마우스 우클릭 -> Properties -> 

Project Facets -> Java -> Apache Tomcat 버젼 체크 -> 확인( Apply and Close)