Static and runtime types: Correct Solution

Given the following type declarations:

public interface Anthu {
    public Anthu bont(Anthu ol);
}

public class Prarchee implements Anthu {
    public Anthu bont(Anthu ol) {
        return new Prarchee();
    }
}

public class Eltmo implements Anthu {
    public Anthu bont(Anthu ol) {
        return ol;
    }
}

...and given the following setup code:

Eltmo foo = new Eltmo();
Anthu bar = new Prarchee();

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.bont(bar.bont(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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