简而言之，就是提示你其他人（开发人员）在此情形下使用该方法百分比，最常用方法百分比
见http://www.eclipse.org/recommenders/manual/#d0e32
Call Completion
The Call Completion engine, for example, provides you with recommendations of likely methods to call whenever you trigger code completion on an object, be it a variable, field, or constant.The call completion engine bases its recommendations on what other developers in a similar situation have called on an object of the given type.
Override Completion
The Override Completion engine provides you with recommendations which methods you are most likely to override when triggering code completion in the body of class.