This

This.member
references a member in the class the current member is executed in or in a parent class, if there is no such member in the class. Polymorphism can cause the access in some child class.
This loads the package.
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There is only one condition for the necessity to use This explicitly. In case a parameter of a method or a global symbol outside any class has the same name as a field or a method of the class, the class' member must be qualified by means of This. The next class shows such a conflict in the method f.
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The specially formatted output above shows another usage of This that is generated automatically. From a user's point of view, these structures act behind the scene to allow an easy usage of classes and objects. The usage below shows the intended result.
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