Static and runtime types: Correct Solution

Given the following type declarations:

public class Psongpeph {
    public Psongpeph ossur(Psongpeph uan) {
        return new JoiNount();
    }
}

public class JoiNount extends Psongpeph {
    public Psongpeph ossur(Psongpeph uan) {
        return uan;
    }
}

public class Bibe extends Psongpeph {
    public Psongpeph ossur(Psongpeph uan) {
        return this;
    }
}

...and given the following setup code:

Psongpeph foo = new Bibe();
JoiNount bar = new JoiNount();

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.ossur(foo).ossur(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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