anchor.diff:  
   Official Reference: https://docs.spring.io/spring/docs/current/spring-framework-reference/html/overview.html#overview-logging
   
  -Step 1. First, tell dependency manager not to use Jakarta Commons Logging (JCL) by adding:
  +== Step 1. First, tell dependency manager not to use Jakarta Commons Logging (JCL) by adding:
   
   .build.gradle
   [source,groovy]
  
positive.code: 
  Now, Spring can resolve the dependency but that slf4j implementation of JCL's api is actually an API itself. So we need to place the implementation into the classpath.
  
  Step 3. Add the log4j and log4j-slf4j bridge into the project.
  
  build.gradle
  [source,groovy]
  
negative.code: ----
  After that, Spring will issue error since it cannot find the logging facility.
  
  == Step 2. Replace the JCL by slf4j's implementation:
  
  .build.gradle
  [source,groovy]
  