例3.12
JPerson.java

public class JPerson  
{
    static String name = "王五";
    int age = 20;
    String country = "中国";

    public static void main(String args[])
    {
        JPerson s1 = new JPerson();
        JPerson s2 = new JPerson();
        JPerson s3 = new JPerson();
    }
}

例3.13
JPerson2.java

public class JPerson2  
{
    static String name = "王五";
    int age = 20;
    String country = "中国";

    public static String setName(String n)
    {
        name = n;
        return name;
    }

    public void setValue(int age, String country)
    {
        this.age = age;
        this.country = country;
    }
}

例3.14
JStaticTest.java

public class JStaticTest  
{
    String testName;

    public static void main(String args[])
    {
        JStaticTest s = new JStaticTest();
        s.testName = JPerson2.name; // 类变量的调用
        System.out.println("testName的值为 " + s.testName);
        s.testName = JPerson2.setName("李四"); // 类方法的调用
        System.out.println("JPerson2.name的值为 " + JPerson2.name);
        System.out.println("现在testName的值为  " + JPerson2.name);
    }
}

例3.15
JBook.java

public class JBook  
{
    public int id; // 书的编号
    public static int bookNumber = 0; // 书的总数

    public JBook()
    {
        ++bookNumber;
    }// JBook构造方法结束

    public void info()
    {
        System.out.println("当前书的编号是：" + id);
    } // 方法info结束

    public static void infoStatic()
    {
        System.out.println("书的总数是：" + bookNumber);
    } // 静态方法引用静态变量

    public static void main(String args[])
    {
        JBook a = new JBook();
        JBook b = new JBook();
        a.id = 1101;
        b.id = 1234;
        System.out.print("变量a对应的");
        a.info();
        System.out.print("变量b对应的");
        b.info();
        JBook.infoStatic();
        System.out.println("比较(a.bookNumber==Book.bookNumber)" + "的结果是："
                + (a.bookNumber == JBook.bookNumber));
        System.out.println("比较(b.bookNumber==Book.bookNumber)" + "的结果是："
                + (b.bookNumber == JBook.bookNumber));
    }
}

例3.16
JStaticUse.java

public class JStaticUse  
{
    static int a = 2;
    static int b;

    static
    {
        b = a * a;
        a = 3;
    }

    public static void main(String args[])
    {
        JStaticUse s1 = new JStaticUse();
        System.out.println("b的值为 " + b);
        JStaticUse s2 = new JStaticUse();
        System.out.println("b的值现在为 " + b);
    }
}

注：本博客内容节选自高飞编著的Java程序设计实用教程 ，详细内容请参阅书籍。