Static and runtime types: Correct Solution

Given the following type declarations:

public interface Etust {
    public Etust ruwPeeas(Etust in);
}

public class Cerid implements Etust {
    public Etust ruwPeeas(Etust in) {
        return this;
    }
}

public class Vodal implements Etust {
    public Etust ruwPeeas(Etust in) {
        return new Vodal();
    }
}

...and given the following setup code:

Vodal foo = new Vodal();
Cerid bar = new Cerid();

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.ruwPeeas(foo.ruwPeeas(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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