Why does Java permit the above code to be executed but C++ doesn't?
Since 2011, C++ also allows class members to be initalised in their declarations.
However, it wouldn't allow this case: you can only instantiate complete types, and a class type is incomplete within the class definition, so it would have to be initialised in the constructor, or by a call to a function:
class Test;
Test * make_test();
class Test {
// Test is incomplete, so "new Test" is not possible here
Test * test = make_test();
};
// Test is complete, so we can instantiate it here
Test * make_test() {return new Test;}
Java doesn't have a concept of incomplete types, so the class can be instantiated anywhere you're allowed to instantiate any class.
Does the code above create infinite objects?
Yes, trying to instantiate such a class would throw your program into a recursive death spiral.
