Confusing Java Class concept

Question

New to java and a concept is confusing me a lot.

As a c++ programmer when we declare a class we can not have a property having an object of same class like lets say we have a class name Foo as belows

class Foo {
int age;
Foo someName;
}

the above code will give error. While in java i can do it. Is there a special reason behind it? And how does it happen. Any good read will be helpful.

Answer 1

When you write Foo someName in Java, you're creating a reference to an object of type Foo. This is similar to writing Foo& someName in C++, which is allowed.

What is not allowed in C++ is for class Foo to have a member of type Foo (i.e. not Foo& or Foo*). If you think about it, this construct can't possibly make sense as it would require sizeof(Foo) to be infinitely large. This -- disallowed -- C++ construct has no direct Java equivalent.