Why string compare is false?

Hello,
I've been confused for a while, could you mind helping?
This small code compare two strings, not know why but always false.
==
String date_zero = "0000-00-00";
out.println("cs is "+date_claim_set); // print "cs is 0000-00-00" on screen
out.println("result is "+date_claim_set.equals(date_zero)); // print "result is false" on screen
if ( ! date_claim_set.equals(date_zero) ) {
out.println("strings not equal"); // printed
==
why the two strings are not equal?
Hope you can help, thanks in advance.
Rgds, Dove

masijade. wrote:
Well, most of his questions lately, have been about MySQL, and "0000-00-00" is the way that MySQL (per default) represents invalid dates, and "YYYY-MM-DD" is the toString() pattern for a java.sql.Date instance. ;-)Sorry for keeping your guys waiting, but I've spent sometimes for reading more material as I can. Now the problem fixed.
The solution is liked this.
1) MySQL document said '0000-00-00' is a valid value for date in DB, but a wrong value for JDBC.
Detail:
http://dev.mysql.com/doc/refman/5.0/en/connector-j-installing-upgrading.html#connector-j-installing-upgrading-3-0-to-3-1
2) It is recognized as a problem, so it has been fixed. Instead of using old JDBC Connector/J, new version with re-configuration of zeroDateTimeBehavior can solve.
I configure it to convertToNull, so in Java I see all value 0000-00-00 from DB as null, works fine.
Many thanks the ideas from all of you.
Rgds, Dove

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[svn] 1751: Bug: BLZ-174 - MessageClient.testMessage() is incorrectly doing a string compare for the subtopic header of an inbound message against the subtopic value (which may contain wildcards) that the Consumer is using.

Revision: 1751
Author: [email protected]
Date: 2008-05-15 14:21:43 -0700 (Thu, 15 May 2008)
Log Message:
Bug: BLZ-174 - MessageClient.testMessage() is incorrectly doing a string compare for the subtopic header of an inbound message against the subtopic value (which may contain wildcards) that the Consumer is using.
QA: No - customer verified the fix.
Doc: No
Ticket Links:
http://bugs.adobe.com/jira/browse/BLZ-174
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blazeds/branches/3.0.x/modules/core/src/java/flex/messaging/MessageClient.java
blazeds/branches/3.0.x/modules/core/src/java/flex/messaging/services/MessageService.java

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String compare question.

Hi all,
I have this code here, and don't understand the result came out. Can someone explain this out come ? Thanks.
String s1 = "Hi";
String s2 = "Hi";
if (s1 ==s2) System.out.println("s1=s2");
String s3 = new String ("Hi");
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if (s3 ==s4) System.out.println("s3=s4");
Result: It only prints "s1=s2". Why is that ?
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Hi all,
I have this code here, and don't understand the result
came out. Can someone explain this out come ?
Thanks.
String s1 = "Hi";s1 is created and put in to the string constant pool. When ever a String literal is encountered, the JVM will first check the string constant pool to see if it already contains a String object with the exactly same data(character sequence). If a match is found, a reference to the existing string is returned, and no new object is created.
String s2 = "Hi";string constant pool is checked and a string literal with the character sequence "Hi" already exists.
So, s1 and s2 are both references to the same object.
if (s1 ==s2) System.out.println("s1=s2");when comparing objects the == operation only tests to see if both references point to the same object. This is true since both s1 and s2 point to the same object in the string constant pool.
String s3 = new String ("Hi");
String s4 = new String ("Hi");A string created with the new operartor is not a string literal. The new operator always generates a unique object and returns a reference to that object.
if (s3 ==s4) System.out.println("s3=s4");
if you wish to compare the contents of a object use the .equals method.
Result: It only prints "s1=s2". Why is that ?
Thanks.
Pwing

String compare QN

Why does the below 2 syntaxes differs although logically they are doing the same thing?
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2) if ((line.substring(0,6)).toString()==temp)

Is there any API on this maybe I can read up for more
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return false, while d.getNodeName() actually equals "production"
The most strange:
Only "production" can broke, never "ingredient".
About 1/3 of all parsed works fine, but after method become "broken" and skips "production" in all parsed nodes.
This bug appears only on production server, and never at developers workstation.
Server:
Linux server 2.6.28-17-server #58-Ubuntu SMP Tue Dec 1 22:13:36 UTC 2009 x86_64 GNU/Linux
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Java(TM) SE Runtime Environment (build 1.6.0_16-b01)
Java HotSpot(TM) 64-Bit Server VM (build 14.2-b01, mixed mode)
Dev:
Win7 Ult
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Java(TM) SE Runtime Environment (build 1.6.0_17-b04)
Java HotSpot(TM) 64-Bit Server VM (build 14.3-b01, mixed mode)

Oblitus wrote:
Which assumptions? I don't know. Like I said: I don't understand what you're trying to say, and I can't be bothered to read your code.
However, I 100% guarantee that you are making some assumptions. Assumptions about how Java works. Assumptions about what your code means to Java. Assumptions about which conditions will be true or not. Assumptions about which variables get assigned which values and when. Assumptions about how your mental idea of your algorithm and you code implemenation of that idea map to each other. And I also guarantee you that at least one of those assumptions is wrong.
So you can choose to believe me, accept that Java is behaving exactly as it's supposed to, or you can assume that the problem is with Java, file a bug report, and find a workaround.
I comparing
"production".equalsIgnoreCase(d.getNodeName()) when d.getNodeName() equals "production" and it returns false!You're assuming that's what's happening. I am highly confident that that assumption is wrong, and that's not really what's happening.
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Why String.getBytes() throws BufferOverflowException exception?

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but sometimes it throws exception like this:
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SUGGESTED WORKAROUND
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Why string compare is false?

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