声明一个国家基类Country，包含国名、首都、人口等属性，派生出省类Province，增加省会城市、人口数量属性。定义派生类对象，并对相应信息进行输出

好的，首先我们声明一个基础的`Country`类，它包含通用的国家属性：

public class Country {
    private String name;
    private String capital;
    private int population;

    // 构造函数
    public Country(String name, String capital, int population) {
        this.name = name;
        this.capital = capital;
        this.population = population;
    }

    // 获取和设置方法
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public String getCapital() { return capital; }
    public void setCapital(String capital) { this.capital = capital; }
    public int getPopulation() { return population; }
    public void setPopulation(int population) { this.population = population; }

    // 打印基本信息
    @Override
    public String toString() {
        return "Country{" +
                "name='" + name + '\'' +
                ", capital='" + capital + '\'' +
                ", population=" + population +
                '}';
    }
}

接着，我们创建一个派生类`Province`，它从`Country`类继承并添加特有的属性：

public class Province extends Country {
    private String provincialCapital;
    private int provincePopulation;

    // 构造函数
    public Province(String name, String capital, int population, String provincialCapital, int provincePopulation) {
        super(name, capital, population); // 调用父类构造函数
        this.provincialCapital = provincialCapital;
        this.provincePopulation = provincePopulation;
    }

    // 获取和设置省会城市和人口数量
    public String getProvincialCapital() { return provincialCapital; }
    public void setProvincialCapital(String provincialCapital) { this.provincialCapital = provincialCapital; }
    public int getProvincePopulation() { return provincePopulation; }
    public void setProvincePopulation(int provincePopulation) { this.provincePopulation = provincePopulation; }

    // 打印更多信息
    @Override
    public String toString() {
        return "Province{" +
                "super.toString() +\n" + // 调用父类toString方法显示基本信息
                "provincialCapital='" + provincialCapital + '\'' +
                ", provincePopulation=" + provincePopulation +
                '}';
    }
}

现在我们可以创建`Country`和`Province`类型的实例并打印它们的信息：

// 创建一个Country实例
Country country = new Country("中国", "北京", 1400000000);
System.out.println(country);

// 创建一个Province实例
Province province = new Province("广东省", "广州", 113400000, "广州市", 113400000);
System.out.println(province);