Classroom Practice 5

Source: Internet
Author: User

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Why do I have to call the construction method of the parent class before the constructor of the subclass is run? Can you turn around? Why can't it be reversed?

The constructor of a subclass must call the constructor of the parent class, sometimes without writing it, and when the parent class has a constructor without arguments, the subclass can not write it out.
Inheritance: If there is a Class A another class B inherits Class A
Then the construction method of Class B will be written
Public B () {super (); }

If a class of construction method has no parameters, this sentence can be omitted, if the class A does not have parameterless construction method, it must be written out, and the parameters to be passed also write to super (parameter);
Function of constructor: Initialization method

Classroom Practice 5

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