public static void main(String[] args){
    System.out.println(String.valueOf(Data.Foo.bar));
    System.out.println(String.valueOf(Data.Foo.array[0].bar));
}

True
False

public class Data {
    public class Base {
        public boolean bar = false;
        public Base[] array = {};
    }

    public class Foo extends Base {
        this.bar = true;
        this.array = {Abc};
    }
    public class Abc extends Base {}
}

public class Data {
    public Foo foo = new Foo();
    public Abc abc = new Abc();

    public class Base {
        public boolean bar = false;
        public Base[] array = {};
    }

    public class Foo extends Base {
        this.bar = true;
        this.array = {abc}; //changed to abc from Abc
    }
    public class Abc extends Base {}
}

public Foo foo = new Foo();
    public Abc abc = new Abc();

public static void main(String[] args) {
    System.out.println(String.valueOf(Datas.getFoo().getBar()));
    System.out.println(String.valueOf(Datas.getFoo().getArray()[0].getBar()));
}

public static void main(String[] args) {
    System.out.println(String.valueOf(Door.isOpen()));
    System.out.println(String.valueOf(Building.getDoors().atIndex(0).isOpen()));
}