public class TestThis_1 {
    public static void main(String[] args) {
        A aa = new A();
        System.out.println(aa.f()); //aa.f(), 返回aa這個對象的引用(指針)
    }  
}

class A {
    public A f() {
        return this;  //返回調(diào)用f()方法的對象的A類對象的引用
    }  
}

class A {
    public int i = 1;                                           //這個i是成員變量

    /*注意:一般不這么寫，構(gòu)造函數(shù)主要是為了初始化，這么寫主要是為了便于理解*/
    public A(int i) {                                           //這個i是局部變量
        System.out.printf("this. i = %d\n", this.i);            //this.i指的是對象本身的成員變量i
        System.out.printf("i = %d\n", i);                       //這里的i是局部變量i
    }  
}

    }  
}

class A {
    int i, j, k;
    public A(int i) {
        this.i = i;
    }  

    public A(int i, int j) {
        /* i = 3;  error   如果不注釋掉就會報錯:用this(...)調(diào)用構(gòu)造方法的時候，只能把它放在第一句
         * TestThis_3.java:20: error: call to this must be first statement in constructor
         *      this(i);
         *                  ^
         *                  1 error
         */
        this(i);   
        this.j = j;
    }  

    public A(int i, int j, int k) {
        this(i, j);
        this.k = k;
    }  
}

    }  
}

class A {
    static A f() {
        return this;
        /* 出錯信息:TestThis_4.java:10: error: non-static variable this cannot be referenced from a static context
         *          return this;
         *                     ^
         *                     1 error
         */
    }  
}