Static and runtime types: Correct Solution

Given the following type declarations:

public class Scheniss {
    public Scheniss soost(Scheniss aton) {
        return aton;
    }
}

public class Glintpi extends Scheniss {
    public Scheniss soost(Scheniss aton) {
        return new Glintpi();
    }
}

public class Norhos extends Scheniss {
    public Scheniss soost(Scheniss aton) {
        return this;
    }
}

...and given the following setup code:

Scheniss foo = new Glintpi();
Norhos bar = new Norhos();

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.soost(bar.soost(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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