FULL PRODUCT VERSION :
java version "1.5.0_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_05-b05)
Java HotSpot(TM) Client VM (build 1.5.0_05-b05, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Linux ncc-1701-e 2.6.11.4-21.9-smp #1 SMP Fri Aug 19 11:58:59 UTC 2005 i686 i686 i386 GNU/Linux SuSE Linux 9.3 (i586)
Linux dauntless 2.6.11 #5 Tue Mar 15 17:45:56 CET 2005 i686 Mobile Intel(R) Celeron(R) CPU 2.40GHz GenuineIntel GNU/Linux Gentoo Base System version 1.4.16
WinXP SP2

A DESCRIPTION OF THE PROBLEM :
There have been a couple of bugs filed about java.lang.String.matches hangs on specific expression. Always the only comment was that their expression is to comprehensive. I've found an example which proves that this is a bug that may occur at any time.

The expression (.*\n*)* works on most Strings but crashes on some. Adding \r* is a workaround but in my opinion not neccessary.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
I wasn't able to find out how the given String has to look like but matching the String "this little fine string lets\r\njava.lang.String.matches\r\ncrash\r\n(We don't know why but adding \r* to the regex makes it work again)" against "(.*\r*\n*)*" works while "(.*\n*)*" crashes

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
System Output as:
true|false
true|false
ACTUAL -
true
- HANGS -

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class MatchesCrash {
    
    public MatchesCrash() {
    }
    
    public static void main(String[] args) {
        String str="this little fine string lets\r\njava.lang.String.matches\r\ncrash\r\n(We don't know why but adding \r* to the regex makes it work again)";
        /* works */
        System.out.println(str.matches("(.*\r*\n*)*"));
        /* crashes */
        System.out.println(str.matches("(.*\n*)*"));
    }
    
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
adding the \r*