Rationale behind constructor call chain... ( and comparison with C++)

Just a question...

If an object B extends an object A, whenever B is constructed, A is
constructed... if A() calls a
function that is overloaded in B, it looks like the overloaded function
is called by the A constructor ...

( In C++ the behavior is always to call the function defined in A when
called within the A constructor, even if the overloaded function is B
is virtual. )

Can someone explain me the rationale behind java's behavior in that
case, how it's useful, more logical etc than the C++ approach... can
this behavior be overriden?

Thanks!

.