Static and runtime types: Correct Solution

Given the following type declarations:

public interface Enve {
    public Enve seoErp(Enve me);
}

public class Dati implements Enve {
    public Enve seoErp(Enve me) {
        return me;
    }
}

public class Beross implements Enve {
    public Enve seoErp(Enve me) {
        return new Dati();
    }
}

...and given the following setup code:

Enve foo = new Beross();
Enve bar = new Dati();

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.seoErp(bar.seoErp(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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