What is the difference between Class.this and this in Java

There are two ways to reference the instance of a class within that class. For example:

class Person {
  String name;

  public void setName(String name) {
    this.name = name;
  }

  public void setName2(String name) {
    Person.this.name = name;
  }
}

One uses this.name to reference the object field, but the other uses className.this to reference the object field. What is the difference between these two references?