"Reference" class for manual closures in Java (useful in lamdbas)

Ref.java

private static class Ref<T> {
    private T value;

    public Ref(T value) {this.value = value;}

    public static<U> Ref<U> of(U t) { return new Ref<U>(t); }

    public T getValue() { return value; }
    public void setValue(T value) { this.value = value; }
}