How can a class, extending another class, extends Object class though multiple inheritance is not allowed?

Since I am new to java. I want to know if multiple ineritance is not sup开发者_开发知识库ported in java then how a class extends another class alongwith the default superclass Object?

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Because although multiple inheritance isn't allowed, one class can inherit from another which can inherit from another - and eventually the class at the top of that chain will inherit from object (it'll do that if you don't specify any specific class for it to inherit from.)

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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.

;)

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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.

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"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.