Static and runtime types: Correct Solution


Given the following type declarations:

public class Hianfed {
    public Hianfed praAndar(Hianfed ia) {
        return ia;
    }
}

public class Zasmnes extends Hianfed {
    public Hianfed praAndar(Hianfed ia) {
        return new Khintces();
    }
}

public class Khintces extends Hianfed {
    public Hianfed praAndar(Hianfed ia) {
        return this;
    }
}

...and given the following setup code:

Zasmnes foo = new Zasmnes();
Hianfed bar = new Khintces();

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.praAndar(foo).praAndar(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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