How can everything be an object? [closed]

Question

In Java for example there is the primitive data type "int" which represents a 32 Bit value and there is "Integer" which is just a class with a single "int" property (and some methods of course). That means that a Java "Integer" class still uses primitives behind the scenes. And that's the reason Java is not a pure object oriented programming language.

Where could a value be stored if there where no primitives? For example I imagine this pseudo class:

class Integer
{
    private Integer i = 12;

    public Integer getInteger
    {
        return this.Integer;
    }
}

This would be recursive.

How can a programming language be implemented without primitives?

I appreciate any help solving my confusion.

Answer 1

Behind the scene always will be primitives because it just a bits in memory. But some languages hide primitives that You can work only with objects. Java allows You to work both with objects and primitives.

Answer 2

If you mean by primitives value types, then yes you can live without them as a user and use Integer instead of int and pay for the overhead of heap allocation and GC. But this doesn't come for free and you have to pay the cost. Primitives like 32-bit/64-bit integers and IEEE-754 floating points will always be faster because there is a hardware support for them.

From a compiler writer point of view you have to use what the machine supports to make things work.