LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation

springboot 실행시 아래와 같은 에러 발생

java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class org.slf4j.impl.Log4jLoggerFactory loaded from jar:file:/Users/user/workspace/aim/server/build/libs/aim-0.0.1-SNAPSHOT.jar!/BOOT-INF/lib/slf4j-log4j12-1.7.30.jar!/). If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml: org.slf4j.impl.Log4jLoggerFactory

찾아보면 logback에서 이미 라이브러리를 선언하고 있으니 slf4j 라이브러리를 제외하면 된다. 

gradle 기준으로 아래와 같이 작성한후 build 

configurations {
    compile.exclude group: "org.slf4j", module: "slf4j-log4j12"
}