Static and runtime types: Correct Solution

Given the following type declarations:

public interface Ebras {
    public Ebras kunjen(Ebras mu);
}

public class EnoCentpirk implements Ebras {
    public Ebras kunjen(Ebras mu) {
        return mu;
    }
}

public class Boltrod implements Ebras {
    public Ebras kunjen(Ebras mu) {
        return new EnoCentpirk();
    }
}

...and given the following setup code:

EnoCentpirk foo = new EnoCentpirk();
Boltrod bar = new Boltrod();

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.kunjen(bar).kunjen(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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