虽然不允许多重继承，但扩展另一个类的类如何扩展Object类？

Question

Since I am new to java. I want to know if multiple ineritance is not supported in java then how a class extends another class alongwith the default superclass Object?

Answer 1

因为虽然不允许多重继承，但是一个类可以从另一个继承另一个类 - 并且最终该链顶部的类将继承自object（如果你没有指定任何特定的类，它会这样做）它继承自。）

Answer 2

Although this is already answered, here is a diferent perspective. Try to think of it in human terms. You can't have 2 biological fathers, but you inherit the traits from your father, your grandfather, great grandfather and so on... In the same way, when you extend a class, that class becomes the parent class and you'll inherit traits from every parent class up the tree.

;)

Answer 3

There are two similar sounding concepts related to inheritance Multiple Inheritance and Multi-Level Inheritance.

Multiple Inheritance is not allowed in java. This stops a class from inheriting multiple classes. For example we can't declare a class as:

Class C extends A, C

But as multilevel inheritance is allowed, extending of class B, which extends class A, by class C is allowed. So class hierarchies like

Class B extends A

and

Class C extends B

is allowed.

Answer 4

"Multiple inheritance" is different than what you describe - it refers to a single class extending more than one class, such as

public class MultipleClass extends ClassA, ClassB

What you have described is just a hierarchy of inheritance.