title: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath
body: <p>I think some module in spring-boot-starter-security is conflict with log4j, but I don't know which one.</p>
  
  <p>my gradle dependence is as following:</p>
  
  <pre><code>compile("org.springframework.boot:spring-boot-starter-thymeleaf")
  compile("org.springframework.boot:spring-boot-starter-security"){
      exclude module: "spring-boot-starter-logging"
  }
  
  compile "org.apache.logging.log4j:log4j-api"
  compile "org.apache.logging.log4j:log4j-core"
  compile "org.apache.logging.log4j:log4j-slf4j-impl"
  compile('org.apache.poi:poi:3.10.1')
  compile('org.apache.poi:poi-ooxml:3.10.1')
  testCompile("junit:junit")
  </code></pre>