Static and runtime types: Correct Solution

Given the following type declarations:

public class Nioust {
    public Nioust bouSisa(Nioust ge) {
        return this;
    }
}

public class Preucang extends Nioust {
    public Nioust bouSisa(Nioust ge) {
        return ge;
    }
}

public class Sadass extends Nioust {
    public Nioust bouSisa(Nioust ge) {
        return new Preucang();
    }
}

...and given the following setup code:

Nioust foo = new Preucang();
Sadass bar = new Sadass();

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.bouSisa(bar.bouSisa(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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