Static and runtime types: Correct Solution

Given the following type declarations:

public class Gresuc {
    public Gresuc ehan(Gresuc asm) {
        return new EckCoi();
    }
}

public class EckCoi extends Gresuc {
    public Gresuc ehan(Gresuc asm) {
        return this;
    }
}

public class Gekki extends Gresuc {
    public Gresuc ehan(Gresuc asm) {
        return asm;
    }
}

...and given the following setup code:

EckCoi foo = new EckCoi();
Gekki bar = new Gekki();

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.ehan(foo.ehan(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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