JAVAP Classroom Exercises--Interface and inheritance

Run Testinherits.java example, observe the output, note the call relationship that summarizes the constructor method between the parent class and the child class modifies The code of the parent constructor method, and explicitly calls grandparent Another constructor, note whether the calling code is the first sentence, which affects significant

class Grandparent {

Public Grandparent () {

System. out. println ("grandparent Created.");

}

Public Grandparent (String string) {

System. out. println ("Grandparent created.string:" + String);

}

}

class Parent extends grandparent {

Public Parent () {

Super ("hello.grandparent.");

System. out. println ("Parent Created");

Super ("hello.grandparent.");

}

}

class Child extends Parent {

Public Child () {

System. out. println ("Child Created");

}

}

Public class Javapingshi {

Public Static void Main (String args[]) {

Child C = new child ();

}

}

Results

In subclasses, to invoke methods overridden in a parent class, you can use the Super keyword.

Class Grandparent {

Public grandparent () {

System.out.println ("Grandparent Created.");

}

Public grandparent (String string) {

System.out.println ("Grandparent created.string:" + String);

}

}

Class Parent extends Grandparent {

Public Parent () {

Super ("hello.grandparent.");

System.out.println ("Parent Created");

Super ("hello.grandparent.");

}

}

Class Child extends Parent {

Public Child () {

System.out.println ("Child Created");

}

}

public class Testinherits {

public static void Main (String args[]) {

Child C = new Child ();

}

}

Program

JAVAP Classroom Exercises--Interface and inheritance