Question

We can make class Foo <T>, why can’t I call new T()?
I tried to understand, I know that T is a type variable, but didn’t get that answer… which is asked by friend, am also eager to know the answer… please, thanks in advance.

Answer 1

Because you cannot know if T is even instantiable, it could have a private constructor.

Imagine:

class Foo<T> {

    public Foo() {
        new T();
    }
}

class Bar {
    private Bar() {}
}

class FooBar {
    public FooBar() {
       Foo<Bar> foo = new Foo<>();
    }
}