Static and runtime types: Correct Solution

Given the following type declarations:

public class Ghessed {
    public Ghessed ubost(Ghessed ial) {
        return ial;
    }
}

public class Tinec extends Ghessed {
    public Ghessed ubost(Ghessed ial) {
        return this;
    }
}

public class Prol extends Ghessed {
    public Ghessed ubost(Ghessed ial) {
        return new Prol();
    }
}

...and given the following setup code:

Prol foo = new Prol();
Ghessed bar = new Tinec();

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.ubost(bar).ubost(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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