Groups > comp.lang.java.programmer > #20545

Re: Need clarification on Object.equals.

Newsgroups	comp.lang.java.programmer
Date	2012-12-19 08:13 -0800
References	<e6f674ec-f00d-4b22-bc02-e1c0ff9ff196@oi3g2000pbb.googlegroups.com> <d8WdnQ4s7tp82k3NnZ2dnUVZ8smdnZ2d@bt.com> <vfp0d8pore6p95616o2tao4isi2jvpsqas@4ax.com> <14r3pk5hnnuce.1fmlq04hracjd.dlg@40tude.net>
Message-ID	<7f86e17c-72f6-4b87-948d-9ee8ad102390@googlegroups.com> (permalink)
Subject	Re: Need clarification on Object.equals.
From	FredK <fred.l.kleinschmidt@gmail.com>

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On Tuesday, December 18, 2012 10:56:19 AM UTC-8, Peter Duniho wrote:
> On Tue, 18 Dec 2012 04:48:16 -0800, Roedy Green wrote: > On Tue, 18 Dec 2012 10:39:27 +0000, lipska the kat > <lipskathekat@yahoo.co.uk> wrote, quoted or indirectly quoted someone > who said : > >>> Node a = new Gate(); >>> Monitor b = new Monitor(); >>> System.out.println(a.equals(b)); // --> prints 'true' > > Gate or one of its superclasses is implementing equals. And doing it incorrectly, I'd say.

Why would you think it was done incorrectly?
For most classes, a.equals(b) is not the same as a==b.
Think about string:
string a = "abc");
string b = new string(a);
Clearly a==b is false, but a.equals(b) is true.

Usually the equals() method returns true if the internal state of both objects is the same.

Thread

Need clarification on Object.equals. "plewto@gmail.com" <plewto@gmail.com> - 2012-12-18 00:13 -0800
  Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-18 10:39 +0000
    Re: Need clarification on Object.equals. Roedy Green <see_website@mindprod.com.invalid> - 2012-12-18 04:48 -0800
      Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-18 10:56 -0800
        Re: Need clarification on Object.equals. FredK <fred.l.kleinschmidt@gmail.com> - 2012-12-19 08:13 -0800
          Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 11:22 -0500
            Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 17:43 +0100
              Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 12:06 -0500
                Re: Need clarification on Object.equals. Patricia Shanahan <pats@acm.org> - 2012-12-19 09:39 -0800
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 13:24 -0500
            Re: Need clarification on Object.equals. FredK <fred.l.kleinschmidt@gmail.com> - 2012-12-19 11:23 -0800
          Re: Need clarification on Object.equals. Patricia Shanahan <pats@acm.org> - 2012-12-19 08:25 -0800
    Re: Need clarification on Object.equals. plewto@gmail.com - 2012-12-18 10:56 -0800
      Re: Need clarification on Object.equals. Jim Janney <jjanney@shell.xmission.com> - 2012-12-18 14:24 -0700
        Re: Need clarification on Object.equals. Patricia Shanahan <pats@acm.org> - 2012-12-18 13:52 -0800
  Re: Need clarification on Object.equals. markspace <-@.> - 2012-12-18 10:24 -0800
    Re: Need clarification on Object.equals. plewto@gmail.com - 2012-12-18 10:48 -0800
      Re: Need clarification on Object.equals. David Lamb <dalamb@cs.queensu.ca> - 2012-12-18 14:01 -0500
        Re: Need clarification on Object.equals. plewto@gmail.com - 2012-12-18 12:14 -0800
          Re: Need clarification on Object.equals. plewto@gmail.com - 2012-12-18 12:17 -0800
            Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-18 22:16 -0500
              Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 10:20 +0000
                Re: Need clarification on Object.equals. Patricia Shanahan <pats@acm.org> - 2012-12-19 03:22 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 12:06 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 09:07 -0500
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 09:09 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 14:36 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 09:42 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 15:05 +0000
                Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 16:15 +0100
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 15:47 +0000
                Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 16:57 +0100
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 16:51 +0000
                Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 18:12 +0100
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 17:27 +0000
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 11:40 -0800
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 10:17 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 15:40 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 10:50 -0500
                Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 17:01 +0100
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 10:22 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 18:49 +0000
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 11:41 -0800
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-19 17:05 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-20 08:34 +0000
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-20 07:27 -0800
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-20 09:04 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-20 18:10 +0000
                Re: Need clarification on Object.equals. Lew <lewbloch@gmail.com> - 2012-12-20 11:08 -0800
                Re: Need clarification on Object.equals. Peter Dunihơ <Np0eStPeAdM@NnOwSlPiAnMk.com> - 2012-12-21 07:50 +0000
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-21 07:30 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-21 17:09 +0000
                Re: Need clarification on Object.equals. Leŵ <lewbl0ch@gmail.com> - 2012-12-23 00:54 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-21 12:23 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-21 17:38 +0000
                Re: Need clarification on Object.equals. Arne Vajhoj <arne@vajhoj.dk> - 2012-12-23 00:50 +0000
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-21 08:39 +0000
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-20 13:39 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-21 08:34 +0000
                Re: Need clarification on Object.equals. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-12-19 09:22 -0600
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 15:35 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 10:56 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 17:08 +0000
                Re: Need clarification on Object.equals. Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-19 08:58 -0600
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 15:32 +0000
                Re: Need clarification on Object.equals. Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-19 11:08 -0600
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 17:32 +0000
                Re: Need clarification on Object.equals. Lars Enderin <lars.enderin@telia.com> - 2012-12-19 18:41 +0100
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 17:58 +0000
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 18:12 +0000
                Re: Need clarification on Object.equals. Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-19 12:29 -0600
                Re: Need clarification on Object.equals. Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-19 12:00 -0600
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 18:06 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 13:13 -0500
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-19 07:48 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 16:48 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 12:09 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 17:50 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 13:14 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 18:59 +0000
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 13:16 -0500
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 19:05 +0000
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 11:45 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 20:00 +0000
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-19 17:15 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-20 09:22 +0000
                Re: Need clarification on Object.equals. Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-12-20 07:36 -0800
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 10:19 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-19 19:16 +0000
                Re: Need clarification on Object.equals. Gene Wirchenko <genew@telus.net> - 2012-12-19 11:48 -0800
                Re: Need clarification on Object.equals. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-12-19 14:12 -0600
                Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 09:04 -0500
                Re: Need clarification on Object.equals. Lew <lewbloch@gmail.com> - 2012-12-19 13:40 -0800
                Re: Need clarification on Object.equals. lipska the kat <lipskathekat@yahoo.co.uk> - 2012-12-20 09:30 +0000
          Re: Need clarification on Object.equals. Lew <lewbloch@gmail.com> - 2012-12-18 12:52 -0800
          Re: Need clarification on Object.equals. Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-19 09:27 -0600
            Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-19 10:44 -0500
      Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-18 22:11 -0500
  Re: Need clarification on Object.equals. Arne Vajhøj <arne@vajhoej.dk> - 2012-12-18 22:10 -0500

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