Static and runtime types: Correct Solution


Given the following type declarations:

public interface Deasche {
    public Deasche cesUrnpru(Deasche eong);
}

public class CluTreshir implements Deasche {
    public Deasche cesUrnpru(Deasche eong) {
        return eong;
    }
}

public class Ionsi implements Deasche {
    public Deasche cesUrnpru(Deasche eong) {
        return this;
    }
}

...and given the following setup code:

Deasche foo = new CluTreshir();
Deasche bar = new Ionsi();

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.cesUrnpru(bar).cesUrnpru(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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