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What is Exemplars?

we can use so called "virtual constructor idiom", i.e. virtual function that creates a new object inside and returns the pointer on is.
In case of Exemplar we simply create a new object, in case of Clone we copy the existing object to the new one:

class Baseclass
{
public: 
	Baseclass(){}
    virtual Baseclass* clone();
    virtual Baseclass* exemplar();
};

Baseclass* Baseclass::clone()
{
	return new Baseclass(*this);
}

Baseclass* Baseclass::exemplar()
{
	return new Baseclass();
}

class Derivedclass : private Baseclass
{
public: 
	Derivedclass(){}
    virtual Derivedclass* clone();
    virtual Derivedclass* exemplar();
};

Derivedclass* Derivedclass::clone()
{
	return new Derivedclass(*this);
}

Derivedclass* Derivedclass::exemplar()
{
	return new Derivedclass();
}

In object-oriented programming, a virtual function or virtual method is a function or method whose behavior can be overridden within an inheriting class by a function with the same signature. This concept is a very important part of the polymorphism portion of object-oriented programming (OOP).

so cloning and overriding is sort of virtual function in java.
check - javadecodedquestions.blogspot.com

hi!
you can get the answer for above examples from c++ idioms wiki book