Verify Classroom Examples:
Testinherits.java
Results:
Thinking:
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