The reason that java creator chosse not to allow multiple inheritance is that it can become quite messy.
The problem is that if a class extends two other classes, and both super classes had, say add() ,which version of add() would the subclass inherit?
This issue can lead to a scenario known as the "deadly diamond of death" because of the shape of the class diagram that can be created in a multiple inheritance design.
The diamond is formed when classes B and C extend A, and both B and C inherit a method from A.
If class D extends both B and C ,and both B and C have overridden the method in A, class D has, in theory, inherited two diff implementations of the same method.
