标签:sys jvm 初始化 tab 对象 oar exce rgs pre
1、如果有父类,先初始化父类,然后初始化子类
2、先初始化静态成员变量、静态代码块(static { }包围的代码),然后初始化非静态成员变量、非静态代码块(大括号包围的代码)。静态成员变量间、非静态成员变量间按定义顺序初始化。
3、调用构造函数
class Bowl { Bowl(int marker) { System.out.println("Bowl(" + marker + ")"); } void f(int marker) { System.out.println("f(" + marker + ")"); } } class Cupboard { Bowl b3 = new Bowl(3); static Bowl b4 = new Bowl(4); Cupboard() { System.out.println("Cupboard()"); b4.f(2); } void f3(int marker) { System.out.println("f3(" + marker + ")"); } static Bowl b5 = new Bowl(5); } class Table { static Bowl b1 = new Bowl(1); Table() { System.out.println("Table()"); b2.f(1); } void f2(int marker) { System.out.println("f2(" + marker + ")"); } static Bowl b2 = new Bowl(2); } public class Test { public static void main(String[] args) throws InterruptedException { System.out.println("Creating new Cupboard() in main"); new Cupboard(); System.out.println("Creating new Cupboard() in main"); new Cupboard(); t2.f2(1); t3.f3(1); } static Table t2 = new Table(); static Cupboard t3 = new Cupboard(); }
1、开始运行,jvm先加载Test类,此时会初始化静态成员变量 t2、t3
2、然后加载Table类,并初始化该类静态成员变量b1、b2,调用Bowl构造 函数生成对象
3、调用Table构造函数,生成t2对象
4、加载Cupboard类,初始化静态成员变量b4、b5,然后非静态成员变量 b3,并调用Bowl构造函数
5、调用Cupboard构造函数,生成t3对象
6、运行main函数
7、运行 new Cupboard,此时Cupboard已加载入内存,静态成员变量不会再初始化,但非静态成员变量仍然再初始化一次
运行结果:
Bowl(1) Bowl(2) Table() f(1) Bowl(4) Bowl(5) Bowl(3) Cupboard() f(2) Creating new Cupboard() in main Bowl(3) Cupboard() f(2) Creating new Cupboard() in main Bowl(3) Cupboard() f(2) f2(1) f3(1)
标签:sys jvm 初始化 tab 对象 oar exce rgs pre
原文地址:http://www.cnblogs.com/yardley/p/7131544.html