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Struts & Hibernate
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| | | Intern | Intern 2005-10-18 - By Bharath Ganesh
Back
Hi
Ya, Java has internal pool of literals.
When u say:
String s1="India"
a string object is created and its ref is put in internal pool.
So next time when u create a new ref for the same string "India", the new ref
will also refer to the same object.
U can also achieve this by saying
String s1=new String("Hello");
String s2=s1.intern();
String s3="Hello";
s2==s3 // Will be true
s1==s2 //False
And u dont get into any risk by sharing the instance cos Strings are immutable.
P.S. Look into intern() in String api.
=====
cheerio
bharath
I Blog at http://jroller.com/page/bharath
-- -- Original Message -- --
From: Sonali Kansara
To: J2EE-INTEREST@(protected)
Sent: Monday, October 17, 2005 6:33 PM
Subject: Re: new String
Yes Frans is right ......... its a concept called interned strings ..........
.
In case of compile time constant strings , a string available from the pool
is utilized instead of creating a new instance of the string .
So
String s1 = "Test5" ;
String s2 = "Test5" ;
String s3 = "Test"+"5" ;
int i = 5 ;
String s4 = "Test"+i ;
Here s1 , s2 , s3 are refering to the same instance of Test5 while s4 creates
a new instance .
Regards ,
Sonali
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<DIV><FONT face=Verdana color=#000080 size=2>
<DIV><FONT face=Verdana color=#000080 size=2>Hi</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT> </DIV>
<DIV><FONT face=Verdana color=#000080 size=2>Ya, Java has internal pool
of literals.</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT> </DIV>
<DIV><FONT face=Verdana color=#000080 size=2>When u say:</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2>String s1="India"</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2>a string object is created and its
ref is put in internal pool. </FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2>So next time when u create a new
ref for the same string "India", the new ref will also refer to the same object
.
</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2>U can also achieve this by saying
</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2>String s1=new
String("Hello");<BR>String s2=s1.intern();<BR>String
s3="Hello";</FONT></DIV><FONT face=Verdana color=#000080 size=2>
<DIV><BR>s2==s3 // Will be true</DIV>
<DIV>s1==s2 //False</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT> </DIV>
<DIV><FONT face=Verdana color=#000080 size=2>And u dont get into any risk by
sharing the instance cos Strings are immutable.</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT> </DIV>
<DIV><FONT face=Verdana color=#000080 size=2>P.S. Look into intern() in String
api.</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT><FONT face=Verdana
color=#000080 size=2></FONT><FONT face=Verdana color=#000080 size=2></FONT>
<FONT
face=Verdana color=#000080 size=2></FONT><BR><FONT face=verdana color=navy
size=2>=====<BR>cheerio <BR>bharath</FONT></DIV>
<DIV><FONT face=verdana color=navy size=2>I Blog at
http://jroller.com/page/bharath </FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
#000080 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">-- -- Original Message -- -- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Sonali.Kansara@(protected) href="mailto:Sonali.Kansara@(protected)">Sonali
Kansara</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=J2EE-INTEREST@(protected)
href="mailto:J2EE-INTEREST@(protected)">J2EE-INTEREST@(protected)</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 17, 2005 6:33
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: new String</DIV>
<DIV><BR></DIV><BR><FONT face=sans-serif size=2>Yes Frans is right .........
its a concept called interned strings ...........</FONT> <BR><BR><FONT
face=sans-serif size=2>In case of compile time constant strings , a string
available from the pool is utilized instead of creating a new instance of the
string .</FONT> <BR><BR><FONT face=sans-serif size=2>So </FONT><BR><BR><FONT
face=sans-serif size=2>String s1 = "Test5" ;</FONT> <BR><FONT face=sans-serif
size=2>String s2 = "Test5" ; </FONT><BR><FONT face=sans-serif
size=2>String s3 = "Test"+"5" ; </FONT><BR><BR><FONT face=sans-serif
size=2>int i = 5 ;</FONT> <BR><FONT face=sans-serif size=2>String s4 =
"Test"+i ;</FONT> <BR><BR><FONT face=sans-serif size=2>Here s1 , s2 , s3 are
refering to the same instance of Test5 while s4 creates a new instance
.</FONT> <BR><BR><BR><FONT face=sans-serif size=2>Regards , </FONT><BR><FONT
face=sans-serif size=2>Sonali </FONT><BR>
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you<BR></FONT></TD></TR></TBODY></TABLE>=====================================
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