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1.д³ö³ÌÐòÔËÐнá¹û
  
public
class
TestString {
    public
static
void
link(String a){
         a+="World"
;
    }
    public
static
void
main(String []args){
         String a = "Hello"
;
         link(a);
         System.out.println(a);
    }
}
´ð: ÕâµÀÌ⿼Á½¸ö·½Ãæ:
1).¡¡String¶ÔÏóµÄÄÚÈÝÊDz»ÄܸıäµÄ,a+="World"²¢²»ÊÇ°ÑaËùÖ¸¶ÔÏó¸Ä±ä,
¡¡¡¡¶øÊÇÏÈÉú³ÉÒ»¸öÁÙʱString¶ÔÏó,ÆäֵΪa+"World",È»ºóÔÚ°ÑÕâ¸öÁÙʱ
¡¡¡¡¶ÔÏ󸳸øa.
2).¡¡JavaÖк¯Êý²ÎÊý´«µÝ·½Ê½ÎªCall by value,link·½·¨ÖлáÉú²úaµÄÒ»¸ö
¡¡¡¡¿½±´,ͬÑùÖ¸ÏòaËùÖ¸µÄ¶ÔÏó,×ÛºÏÒÔÉÏÁ½µã,µÃ³ö½á¹ûΪ Hello
 
2. д³öÏÂÃæ´úÂëµÄ½á¹û
 
System.out.println(
"
ja
"
+
"
va
"
 
==
 
"
java
"
);
 
´ð:"=="ÓÃÀ´±È½Ï¶ÔÏóµÄÒýÓÃ,¶øequals()ÓÃÀ´±È½Ï¶ÔÏóµÄÄÚÈÝ,µ«ÊÇÈç¹ûÊÇ×Ö·û´®³£Á¿,ÓÃ"=="Ò²¿ÉÒԱȽÏÄÚÈÝ
ÊÇ·ñÏàµÈ,"ja"+"va"ºÍ"java"¶¼ÊÇ×Ö·û´®³£Á¿,Òò´Ë½á¹ûΪtrue
ͬÀí,ÏÂÃæ´úÂë½á¹ûÒ²ÊÇtrue
 
final
 String str 
=
 
"
java
"
;
System.out.println(str
==
"
java
"
)
 
3.¼Ì³ÐʱºòÀàµÄÖ´ÐÐ˳ÐòÎÊÌâ,Ò»°ã¶¼ÊÇÑ¡ÔñÌâ,ÎÊÄ㽫»á´òÓ¡³öʲô?
public
class
Parent {
    //1
    static
int
a = 1;
    //2
    static
  
    {
       a=10;
       System.out.println("parent static
code"
);
    }
    //4
    public
Parent(){
      System.out.println("Parent constructor