Updated Essay.java
Added UML diagram and java-doc style comment.
Removed unnecessary import.
Updated Essay.java
Change method checkScore from public to private.
Updated Essay.java
Moved author name to the beginning of the file.
Updated Employee.java
Moved author name to the beginning of the file.
Updated TeamLeader.java
Moved author name to the beginning of the file.
Added UML diagram.
Added java-doc style comment.