java變量初始化
class?Singleton?{????
????private?static?Singleton?singleton?=?new?Singleton();????
????public?static?int?counter1;????
????public?static?int?counter2?=?0;????
????private?Singleton()?{
????????counter1++;
????????counter2++;
????}????
????public?static?Singleton?getInstance()?{???????
?????????return?singleton;
????}
}
public?class?TestSingleton?{
????public?static?void?main(String[]?args)?{
????????Singleton?s?=?Singleton.getInstance();
????????System.out.println(Singleton.counter1);
????????System.out.println(Singleton.counter2);
????}
}輸出結(jié)果是1，0
為什么
2018-09-26
Java對于靜態(tài)成員變量的初始化，分解為兩步執(zhí)行。
1. 根據(jù)靜態(tài)成員變量在代碼中的先后次序進行聲明并賦值為缺省值2. 在靜態(tài)塊內(nèi)依次為變量進行賦值