There's a good old acronym that says RFM, which in this case states: "Method parameters name argument values passed to a method. For every parameter declared in a method declaration, a new parameter variable is created each time that method is invoked. The new variable is initialized with the corresponding argument value from the method invocation. The method parameter effectively ceases to exist when the execution of the body of the method is complete."
Section 2.5 of the Java Virtual Machine Specification This means that there is no such thing as pass by reference in Java and if you think that this is just semantics then you've never had to port a program from C to Java... :) br -----Original Message----- From: David Gallardo [mailto:[EMAIL PROTECTED]] Sent: Friday, May 31, 2002 3:50 PM To: JDJList Subject: [jdjlist] Re: Java : pass by reference??? Semantics--he's quibbling with you about semantics. In Java, some people don't like to call it "passing by references." In certain quarters, they'll boo you down & not let you finish your sentence, if you use that term. (Despite the references someone quoted, I can think of a few other books that unabashedly call it passing by reference. But in any case, "appeal to authority" is a weak argument.) It says something about the confusion this causes, that you, who got the official terminology wrong, are the only one who got the answer right! --- Nathan Tenney <[EMAIL PROTECTED]> wrote: > Perhaps I am wrong, but I understood passing a > reference to an object to be termed pass by > reference... > > --- Tom Jordan <[EMAIL PROTECTED]> wrote: > > Nathan, > > > > You are description of the "fillMe" argument and > the > > effect of the "fill()" > > method is correct, but your assertion that "Java > > does use pass by reference" > > is WRONG. > > > > The following statement is absolutely true: "Java > > passes all arguments by > > VALUE" (references listed below). > > > > When passing an Object it is the object reference > > that gets passed (not the > > object itself) and it is passed by value. In other > > words, a copy of the > > object reference is passed to the method. As you > > correctly stated, this > > reference points the orginal object and can be > used > > to modify the orginal > > object thru its public mutator methods. > > > > Tom > > > > References: > > "Exploring Java" 2nd edition, O'Reilly, Pg 143 > > "Argument Passing and > > References" > > "Java 2 Certification Study Guide", Sybex, Pg 17 > > "Argument Passing" > > > > > > > > -----Original Message----- > > From: Nathan Tenney [mailto:[EMAIL PROTECTED]] > > Sent: Friday, May 31, 2002 12:36 PM > > To: JDJList > > Subject: [jdjlist] Re: Java : pass by reference??? > > > > > > Ok, I didn't take the time to read all the > messages > > in > > this thread, so someone may have already answered > > this > > to my satisfaction, but the 4 or 5 I did read had > it > > totally wrong. > > > > Java does use pass by reference. Think of the > > variable fillMe in your fill methods has holding a > > reference to another object. At the beginning of > > the > > method, it refers to the object you passed in when > > you > > called fill. However, when you used new, you > > changed > > which object fillMe refers to, so any changes made > > to > > fillMe at this point will not touch the original > > object fillMe referred to. NOTE: defining a > String > > explicitly (with "") is the same thing as using > new. > > > > The major problem with your example is that you > used > > immutable objects (String and Integer) as the > > objects > > to refer to. Immutable Objects are those that > have > > no > > methods for modifying the data that is stored in > > them. > > All you can do with them is create new Objects. > > Try > > this example with StringBuffer instead of String, > > and > > replace fillMe = "test"; with fillMe.append(" > > test"); > > and you will see a difference in your output. > > > > Hope that was easy to understand. > > > > --- H Shankaranarayanan <[EMAIL PROTECTED]> > > wrote: > > > class test > > > { > > > /** > > > * Description of the Method > > > * > > > *@param fillMe Description of the > Parameter > > > */ > > > public void fill(String fillMe) > > > { > > > fillMe = "test"; > > > } > > > > > > > > > /** > > > * Description of the Method > > > * > > > *@param fillMe Description of the > Parameter > > > */ > > > public void fill(Integer fillMe) > > > { > > > fillMe = new Integer(100); > > > } > > > > > > > > > /** > > > * Description of the Method > > > * > > > *@param args Description of the Parameter > > > */ > > > public static void main(String args[]) > > > { > > > > > > try > > > { > > > test objTest = new test(); > > > String testfill = new > String("main"); > > > objTest.fill(testfill); > > > System.out.println("Fill me result:" > + > > > testfill); > > > > > > Integer intFill = new Integer(200); > > > objTest.fill(intFill); > > > System.out.println("Fill me result:" > + > > > intFill); > > > > > > } catch (Exception e) > > > { > > > e.printStackTrace(); > > > } > > > } > > > } > > > > > > > > > That is a sample program i wrote to test this > > fact. > > > The result is dependent > > > on scope of the variable. > > > So wots this pass by reference concept that > every > > > text book around the world > > > states about Java. > > > > > > How does the pass by reference concept work > > anyways? > > > > > > I might have missed something here. If i did i > > would > > > appreciate if anyone > > > told me wot is it that i did miss. > > > > > > I was expecting this program to work otherwise > but > > > it does not. > > > > > > --Shankar > > > > > > > > > To change your membership options, refer to: > > > http://www.sys-con.com/java/list.cfm > > > > > > ===== > > ---------------------------------- > > Nathan Tenney > > Alumni Utah State University > > [EMAIL PROTECTED] > > ---------------------------------- > > > > __________________________________________________ > > Do You Yahoo!? > > Yahoo! - Official partner of 2002 FIFA World Cup > > http://fifaworldcup.yahoo.com > > > > To change your membership options, refer to: > > http://www.sys-con.com/java/list.cfm > > > > > > THIS TRANSMISSION, INCLUDING ANY ATTACHMENTS OR > > FILES, > > CONTAINS AIRNET COMMUNICATIONS CORPORATION > > CONFIDENTIAL > > AND PROPRIETARY INFORMATION WHICH MAY BE OTHERWISE > > EXEMPT > === message truncated === __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com To change your membership options, refer to: http://www.sys-con.com/java/list.cfm To change your membership options, refer to: http://www.sys-con.com/java/list.cfm
