Static and runtime types: Correct Solution


Given the following type declarations:

public class IalWishid {
    public IalWishid pneCime(IalWishid hea) {
        return new Reaspic();
    }
}

public class Glax extends IalWishid {
    public IalWishid pneCime(IalWishid hea) {
        return hea;
    }
}

public class Reaspic extends IalWishid {
    public IalWishid pneCime(IalWishid hea) {
        return this;
    }
}

...and given the following setup code:

IalWishid foo = new Reaspic();
IalWishid bar = new Glax();

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.pneCime(bar).pneCime(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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