Why java disallows multiple inheritance

In your example, JVM would not be able to identify the super class constructor which needs to be called when you create object of class D. Correct me if im wrong…. Most languages are adding support for multiple inheritance, including Java in Java 8. Conceptually, single inheritance is simpler at the cost of making the overall program harder and more verbose to express.

The diamond problem is simple to resolve. See Eiffel, Scala and Haskell for how useful multiple inheritance is. I think your claim that multiple inheritance is rarely used is a poor one. They work around it by reimplementing MI using composition at the cost of extra code and defects.

I think you could learn alot by learning more fundamentals of computer science, rather than being Java focussed. The argument is quite weak actually. Is it an excuse to stay ignorant? Got it? There you go. Why not do the same for multiple inheritance? It is nice article on Multiple Inheritance. But then what is the use of Interface in java?. Can you clearly explain about that? Since Abhishek says:. Anonymous says:. Manishkumar Modi says:. Asraful Forhad Chowdhury says:.

Jim says:. Leo says:. Arvind says:. Nick says:. Joe says:. Radhika says:. Praveen J says:. SrinivasaraoVanapalli says:. Vijay says:. Sarath Kumar N says:. Balaji Reddy says:. Amit Singh says:. Sumit Singh says:. Jack9 says:. Akhil says:. Shubha says:. Sultan says:. Shiv says:. Jobin says:. Harsh says:. Arun says:. Rahul sharma says:.

Kiran says:. K Shiv says:. Om says:. Gayathri Chitnhala says:. Muthusamy says:. Manzar Baig says:. Anwar says:. Nagaraju Gurram says:. Nupur says:. Sandy says:. PMJ says:. Ankur says:. Prakash Gavade says:. Rajashekhar says:. Rohit Kumar Prusty says:. Rajesh says:. Dinesh says:. LJ says:. Waleed says:. Serg says:. Rakesh says:. Jaywant Patil Java Developer says:. Saifuddin Syed says:. Balu Nehe says:. Pranav says:. Dhiren says:. Iranna Yalavatti says:. Shiva says:.

Naman says:. Avishek says:. Shinod says:. Ashesh says:. Sreekanth says:. Sree says:. Mark says:. As a simple language, Java's creators wanted a language that most developers could grasp without extensive training. In the designers' opinion, multiple inheritance causes more problems and confusion than it solves.

So they cut multiple inheritance from the language just as they cut operator overloading. Instead, Java's designers chose to allow multiple interface inheritance through the use of interfaces, an idea borrowed from Objective C's protocols. Multiple interface inheritance allows an object to inherit many different method signatures with the caveat that the inheriting object must implement those inherited methods.

Multiple interface inheritance still allows an object to inherit methods and to behave polymorphically on those methods. The inheriting object just doesn't get an implementation free ride. For an excellent discussion of interface inheritance, read Wm.

This story, "Why not multiple inheritance? The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why doesn't java allow multiple inheritance of classes when it allows multiple inheritance of interfaces? Asked 4 years, 10 months ago. Active 4 years, 10 months ago. Viewed 2k times. Improve this question. SteelToe SteelToe 1, 3 3 gold badges 10 10 silver badges 21 21 bronze badges.

Ever heard of diamond hierarchy problem? I really don't like the term "inheritance of interfaces". I'd rather use "implementation of multiple interfaces". Inheritance implies that you're receiving something ready and for free, while implementation defines you have an obligation. They're totally opposites in this context in my opinion.

Much as I wanted to make this an answer, my memory had too many holes, but: another reason Java doesn't do MI is due to the way method pointers are stored. They're offsets from the beginning of a class definition in a classfile.

This has critical implications for how the bytecode instructions invokestatic , invokespecial , and invokevirtual work. IIRC, invokevirtual works faster than it would otherwise, because it can rely on certain methods being at certain offsets. Interface methods don't threaten this.

Multiple classes, however, would. Add a comment. Active Oldest Votes. Improve this answer. Winston Ewert Winston Ewert Would I be correct in saying you ment "each of which have a foobar field "? JimmyJames JimmyJames Why multiple inheritance is not more popular? Lucas Lucas 1 1 silver badge 4 4 bronze badges. The Overflow Blog.

Does ES6 make JavaScript frameworks obsolete?