Static and runtime types: Correct Solution

Given the following type declarations:

public interface Mamim {
    public Mamim stos(Mamim si);
}

public class Arptoint implements Mamim {
    public Mamim stos(Mamim si) {
        return si;
    }
}

public class Stek implements Mamim {
    public Mamim stos(Mamim si) {
        return new Stek();
    }
}

...and given the following setup code:

Mamim foo = new Arptoint();
Mamim bar = new Stek();

Part 1

Draw an AST for the following expression, labeling the static type (a.k.a. compile-time type) of each node in the tree:

foo.stos(bar).stos(bar)

(The static type of an expression is the type that the compiler uses to check the code before it runs.)

Solution

Part 2

Draw an AST for the same expression, this time labeling the runtime type of each node in the tree.

(The runtime type of an expression is the type of the actual value that appears when the code runs.)

Solution

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