【Spark】. Explanation of several icons of scala file in idea

• Yellow big O： Indicates that there is only one companion object in the current file .

• There are two red bars in the lower right corner of the document ： When there are more than companion objects in the file , There are other classes or other things .

• There is a in the blue circle C： Indicates that there is only one... In the file class.

• Half blue, half yellow ： Indicates that there is a class and a companion object , And the class name is the same as the name of the associated object .