Re: Java 1.4.2, I need a set of unique strings

From:

Eric Sosman <Eric.Sosman@sun.com>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 02 Oct 2008 17:05:07 -0400

Message-ID:

<1222981510.259009@news1nwk>

Donkey Hottie wrote:

Patricia Shanahan <pats@acm.org> wrote in news:gc3932$11bn$1
@ihnp4.ucsd.edu:

Donkey Hottie wrote:

I'm parsing data from disk, and need to keep a collection of Strings in
memory.

Java does not consider

String s1 = "Abba" ;
String s2 = "Abba" ;

Since they are equal and both String constant expressions, they will be
represented by the same String object.

No, they will not.

Donkey Hottie, you are making of yourself a one-syllable synonym
of the first half of your name.

You can yeasily try this and see.

s1 == s2 will result to false.

     Try it yourself. Here, just copy and paste:

    public class Donkey {
        public static void main(String[] unused) {
            String s1 = "Abba" ;
            String s2 = "Abba" ;
            System.out.println(s1 == s2);
        }
    }

You say the output will be "false"; I say it will be "true". I will
bet you one hundred gold splonders that you are wrong. Are you on?

And in my application they will not be constants, they will be read from a
file.

Ah, but that's an entirely different matter! If you don't
understand why it's different, it may be time to review your Java
text again; most will explain this point. If you can't find it
there, see section 3.10.5 of the Java Language Specification.
The five bullet points at the end of the section will probably
be eye-openers for you.

--
Eric.Sosman@sun.com