multiple-inheritance

Is java.lang.Object superclass of all the custom class/objects inherited implicitly? I thought java didn't support multiple inheritance. The reason I ask is if I already inherit from another class in my custom class and again java is forcing implicit inheritance of java.lang.Object on top of it, is it not multiple inheritance? Also, is java.lang.class Class also the superclass for all custom classes/Objects? If not, how in java reflections we can get the type of class for any class passed or call isInstance on any object? Everything is an Object, that said you could see the structure as this:

I'm writing some code involving inheritance from a basic ref-counting pointer class; and some intricacies of C++ popped up. I've reduced it as follows: Suppose I have: class A{}; class B{}; class C: public A, public B {}; C c; C* pc = &c; B* pb = &c; A* pa = &c; // does pa point to a valid A object? // does pb point to a valid B object? // does pa == pb ? Furthermore, does: // pc == (C*) pa ? // pc == (C*) pb ? Thanks! does pa point to a valid A object? does pb point to a valid B object? Yes, the C* gets converted so that pa and pb point to the correct addresses. does pa == pb ? No, usually

I have an abstract base class which acts as an interface. I have two "sets" of derived classes, which implement half of the abstract class. ( one "set" defines the abstract virtual methods related to initialization, the other "set" defines those related to the actual "work". ) I then have derived classes which use multiple inheritance to construct fully defined classes ( and does not add anything itself ). So: ( bad pseudocode ) class AbsBase { virtual void init() = 0; virtual void work() = 0; } class AbsInit : public AbsBase { void init() { do_this(); } // work() still abs } class AbsWork :

I have a basic question related to multiple inheritance in C++. If I have a code as shown below: struct base1 { void start() { cout << "Inside base1"; } }; struct base2 { void start() { cout << "Inside base2"; } }; struct derived : base1, base2 { }; int main() { derived a; a.start(); } which gives the following compilation error: 1>c:\mytest.cpp(41): error C2385: ambiguous access of 'start' 1> could be the 'start' in base 'base1' 1> or could be the 'start' in base 'base2' Is there no way to be able to call function start() from a specific base class using a derived class object? I don't know

A new feature coming in JDK 8 allows you to add to an existing interface while preserving binary compatibility. The syntax is like public interface SomeInterface() { void existingInterface(); void newInterface() default SomeClass.defaultImplementation; } This way for all existing implementations of SomeInterface when they upgrade to this new version they don't all suddenly have compiles errors around newInterface() . While this is neat, what happens when you are implementing two interfaces which both have added a new defaulted method which you did not implement? Let me explain with an example.

It's often stated that super should be avoided in Python 2. I've found in my use of super in Python 2 that it never acts the way I expect unless I provide all arguments such as the example: super(ThisClass, self).some_func(*args, **kwargs) It seems to me this defeats the purpose of using super() , it's neither more concise, or much better than TheBaseClass.some_func(self, *args, **kwargs) . For most purposes method resolution order is a distant fairy tale. Other than the fact that 2.7 is the last major release to Python 2, why does super remain broken in Python 2? How and why has Python 3's