Answer to this question is yes, java does not support
multiple inheritance but by introducing the concept of interface it just gives
the feeling of multiple inheritance but still it is not multiple inheritance.
Multiple inheritance means inheriting more than one class
into single class. A class may implement more than one interface but it can
inherit only one class. Interface does not contain method implementation but it
contains abstract methods which need to be implemented by the class which uses
that interface. So it just gives feeling of multiple inheritance but it is not
multiple inheritance as the class which uses those interfaces must implement
the methods present in those interfaces.
In the above diagram, two classes B and C are
derived from same class A and class D is derived from two classes B and C using
multiple inheritance. The problem with above type of inheritance is that when
an instance of D is calling any method of class A, it is not clear whether to
call version of method derived from class B or class C. You can see in the
figure above that the classes essentially form the shape of a diamond, this
problem is called the diamond problem.
In the designers' opinion, multiple inheritance causes more problems and confusions than it solves. The use of multiple inheritance results into diamond problem so for the sake of simplicity, multiple inheritance is not supported in java.
