如何在Java中从基类的方法返回派生类的对象？

class BaseClass {
    public BaseClass createObject() {
        return new BaseClass();
    }
}

class DerivedClass extends BaseClass {
    @Override
    public DerivedClass createObject() {
        return new DerivedClass();
    }
}

// 使用多态，返回派生类对象
BaseClass obj = new DerivedClass().createObject();

class BaseClass {
    public <T extends BaseClass> T createObject() {
        return (T) new BaseClass();
    }
}

class DerivedClass extends BaseClass {
    @Override
    public DerivedClass createObject() {
        return new DerivedClass();
    }
}

// 使用泛型，返回派生类对象
DerivedClass obj = new DerivedClass().<DerivedClass>createObject();

class BaseClass {
    public static BaseClass createObject() {
        return new BaseClass();
    }
}

class DerivedClass extends BaseClass {
    public static DerivedClass createObject() {
        return new DerivedClass();
    }
}

// 使用工厂模式，返回派生类对象
BaseClass obj = DerivedClass.createObject();