Static and runtime types: Correct Solution

Given the following type declarations:

public interface Owiss {
    public Owiss ceift(Owiss ia);
}

public class Fucan implements Owiss {
    public Owiss ceift(Owiss ia) {
        return new Fucan();
    }
}

public class Saentron implements Owiss {
    public Owiss ceift(Owiss ia) {
        return ia;
    }
}

...and given the following setup code:

Fucan foo = new Fucan();
Owiss bar = new Saentron();

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.ceift(foo).ceift(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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