Java hands-on brain-Interface inheritance

1. Testinherits.java

　　

　　

After you explicitly call another constructor of grandparent, the result is as follows:

　　

　　

2. Function of constructors

A constructor method of the parent class must be called in the constructor of the subclass, which is the constructor of the child class that can be specified by super to call the parent class, and if not specified, the parent class is automatically called without a parameter constructor when the child class object is instantiated. You can explicitly call a parent class in a subclass that already has a constructor method, or a constructor that has no parameters defined in the parent class.

3.address.java

　　

4.explorationjdksource.java

　　

5.fruit.java

　　

Java hands-on brain-Interface inheritance