Re: [問題] 請教物件生成的流程

[Oreilly (怕寂寞卻愛自由)]

MyClass my=new MyClass();

這行code做了以下事情

step1.宣告 MyClass型態的變數my
step2.在heap上建立MyClass  物件
step3.執行MyClass的建構子
step4.把記憶體的位置 asign reference給變數my

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
可是這篇文章
http://www-128.ibm.com/developerworks/java/library/j-dcl.html

Listing 6. Assembly code produced from code in Listing 5

;asm code generated for getInstance
054D20B0   mov         eax,[049388C8]      ;load instance ref
054D20B5   test        eax,eax             ;test for null
054D20B7   jne         054D20D7
054D20B9   mov         eax,14C0988h
054D20BE   call        503EF8F0            ;allocate memory
054D20C3   mov         [049388C8],eax      ;store pointer in
                                           ;instance ref. instance
                                           ;non-null and ctor
                                           ;has not run
054D20C8   mov         ecx,dword ptr [eax]
054D20CA   mov         dword ptr [ecx],1   ;inline ctor - inUse=true;
054D20D0   mov         dword ptr [ecx+4],5 ;inline ctor - val=5;
054D20D7   mov         ebx,dword ptr ds:[49388C8h]
054D20DD   jmp         054D20B0
這篇文章推論出
step3和step4順序應該倒過來
這在多執行緒的情況下是合理的

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

所以小弟我只想知道單一執行緒底下且不考慮繼承
有沒有人能證明物件生成的流程

感謝ing...


--
dd

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 61.221.67.175