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Why Java doesn't support Multiple Inheritance?

Has it ever occurred to you why Java doesn't support Multiple Inheritance being developed in C and C++ which supports Multiple Inheritance?

Here's why.

  • Assume there are 4 classes named class A, class B, class C and class D. B and C are derived from A and D is derived from both B and C using Multiple Inheritance.




  • A will contain a method 'find()' which will be inherited by B and C.




  • When we create an object from D and try to call this find() method as below,

                        D d = new D();
                        d.find();

JVM is confused as to which method to use!!! since both B and C contains an overridden find() method.

This is known as The Deadly Diamond of Death.

In languages like C and C++ you have to use other workarounds as a solution.

But since Java does not support Multiple Inheritance, this is not an issue.

However, you can have a similar implementation to Multiple Inheritance in Java using Interfaces.

If you wonder how the Diamond of Death is overcome by that, this is how,
  • In an implementation as below, when B and C are interfaces, D will simply be asked to implement the find() method with its own implementation.
                                  
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