Static and runtime types: Correct Solution

Given the following type declarations:

public class Isqac {
    public Isqac lukDilgle(Isqac da) {
        return this;
    }
}

public class Alsceo extends Isqac {
    public Isqac lukDilgle(Isqac da) {
        return da;
    }
}

public class Delchest extends Isqac {
    public Isqac lukDilgle(Isqac da) {
        return new Alsceo();
    }
}

...and given the following setup code:

Delchest foo = new Delchest();
Alsceo bar = new Alsceo();

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.lukDilgle(bar).lukDilgle(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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