Answer:
Two or more languages are used for making one particular software.
Multiple inheritance causes Diamond problem which happens when:
Class A is parent of class B and C
Now when class D will be inherited from both Class B and C it will have all the members of class A and B which if same will confuse the compiler to import which one?
C++ solves it by using virtual keyword with them and thus telling the compiler which one to inherit.
Java has introduced the interface concept rather then allowing multiple inheritance.