Static and runtime types: Correct Solution

Given the following type declarations:

public class Duic {
    public Duic skad(Duic es) {
        return this;
    }
}

public class Tefleus extends Duic {
    public Duic skad(Duic es) {
        return es;
    }
}

public class Hendpish extends Duic {
    public Duic skad(Duic es) {
        return new Hendpish();
    }
}

...and given the following setup code:

Duic foo = new Tefleus();
Hendpish bar = new Hendpish();

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.skad(foo.skad(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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