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Java Forum / General / November 2005how can this happen?
Here's the message I get from a PatternSyntaxException Unknown character category {Digit} near index 8 \p{Digit}{1,2} ^ How can this be? {Digit} is a valid character category, it's in the javadoc, it's even in the source code. (Incidentally the single \ is how java reports the error, in the source I have "\\p{Digit}{1,2}") I'm using java 1.4.2_06 and running under BEA Weblogic 8.1 john > Here's the message I get from a PatternSyntaxException > [quoted text clipped - 7 lines] > > I'm using java 1.4.2_06 and running under BEA Weblogic 8.1 Works for me. Also 1.4.2._06, OS is Windows 2k Server, no app server. robert > > Here's the message I get from a PatternSyntaxException > > [quoted text clipped - 11 lines] > > robert Works for me as well when I run as a standalone Java app, baffling. john >Unknown character category {Digit} near index 8 >\p{Digit}{1,2} you did not post your code so I wrote this SSCCE import java.util.regex.Matcher; import java.util.regex.Pattern; /** * snippet ™ to demonstrate a problem with regex */ public class Regex4 { private static final Pattern p = Pattern.compile("(\\p{Digit}){1,2}"); /** * test harness * * @param args not used */ public static void main ( String[] args ) { // format 1 Matcher m = p.matcher("89"); m.matches(); int count = m.groupCount() + 1; // display groups found for ( int i=0; i<count; i++ ) { System.out.println(m.group(i)); } } } When I ran it on JDK 1.5.0_05 it gave the following results: 89 9  SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. > >Unknown character category {Digit} near index 8 > >\p{Digit}{1,2} > > you did not post your code so I wrote this SSCCE My real code is a few lines inside a large J2EE application. I know that if I extract the code and run it in a different environment then it will work fine. My interest is in suggestions for what could possibily be going wrong for the JVM not to recognise a perfectly standard character category. If you look at the source for Pattern then the character categories are looked up in a simple map, in a single place in the code. How could this go wrong? That's my question. >>> Unknown character category {Digit} near index 8 >>> \p{Digit}{1,2} [quoted text clipped - 10 lines] > are looked up in a simple map, in a single place in the code. How > could this go wrong? That's my question. Maybe some wired threading or class loading issue... Just a wild guess. robert > > If you look at the source for Pattern then the character categories > > are looked up in a simple map, in a single place in the code. How [quoted text clipped - 3 lines] > > robert Hmm, I'm no java expert but if you look at the code in Pattern you see this private Node retrieveCategoryNode(String name) { if (categories == null) { int cns = categoryNodes.length; categories = new HashMap((int)(cns/.75) + 1); for (int x=0; x<cns; x++) categories.put(categoryNames[x], categoryNodes[x]); } Node n = (Node)categories.get(name); if (n != null) return n; return familyError(name, "Unknown character category {"); } categories is a HashMap of the known categories. It's a static member. The thing that strikes me is that the creation of the map is not synchronised, so is it possible that one thread could be in the process of populating the categories when another thread comes along and uses the part populated map? As I say, I'm no expert in java. Could someone with more expertise confirm if this is plausible? > Hmm, I'm no java expert but if you look at the code in Pattern you see > this [quoted text clipped - 14 lines] > > categories is a HashMap of the known categories. It's a static member. Ugh! Unless there's something subtle that I've missed, that code is completely broken. It isn't even /nearly/ right (it could at least wait unless the new HashMap was populated before assigning it to the 'categories' variable -- which would still be technically incorrect). That code has been completely replaced in 1.5.0 by something that /is/ correct (I think). Can you force the Pattern initalisation to happen early (before any of your real threads are running) by compiling a throwaway Regex during some sort of system initialisation phase ? -- chris >As I say, I'm no expert in java. Could someone with more expertise >confirm if this is plausible? Try some code that "warms up" the Pattern class. You might even sleep. Pattern dummy Pattern.compile("a"); Pattern p = Pattern.compile("(\\p{Digit}){1,2}"); SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. >> If you look at the source for Pattern then the character categories >> are looked up in a simple map, in a single place in the code. How >> could this go wrong? That's my question. did Bea reimplement Regex for speed and simply failed to test adequately. If you can get my code into Bea and get it to fail, you can submit it as a bug report. SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. > My real code is a few lines inside a large J2EE application. I know > that if I extract the code and run it in a different environment then [quoted text clipped - 5 lines] > looked up in a simple map, in a single place in the code. How could > this go wrong? That's my question. The only thing I can think of is that your code is somehow picking up a different implementation of Pattern when it's runing in your J2EE environment. Might be worth scanning all the directories, JARs, etc, to see if there are any candidates for confusion. -- chris jahhaj coughed up: >>> Unknown character category {Digit} near index 8 >>> \p{Digit}{1,2} [quoted text clipped - 4 lines] > that if I extract the code and run it in a different environment then > it will work fine. Two ideas pulled out of someplace fairly dark: 1. Don't run it in a different environment. Extract it and keep it as much as possible in the /same/ environment. 2. Don't "extract" it at all. Instead /pair down/ the problem code as much as you can, possibly by putting in the testing code around the issue, and keep testing until you remove something and see the problem go away. This is a technique that works very well to expose many things. Even if your paired down version ends up looking just like the extracted version you already attempted, there might be a smidgeon of a detail missing that will illuminate the problem. I hope this applies to your issue. YMM(ofcourse)V. > My interest is in suggestions for what could > possibily be going wrong for the JVM not to recognise a perfectly [quoted text clipped - 3 lines] > looked up in a simple map, in a single place in the code. How could > this go wrong? That's my question. SignatureOnedoctortoanother:"Ifthisismyrectalthermometer,wherethehell'smypen???" hi u can use "\\d{1,2}" > Here's the message I get from a PatternSyntaxException > > Unknown character category {Digit} near index 8 > \p{Digit}{1,2} > ^ Thanks to everyone who replied to my query. Turns out this is a known bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6238699 Really, really poor coding by Sun. john >Thanks to everyone who replied to my query. Turns out this is a known >bug > >http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6238699 > >Really, really poor coding by Sun. So the bug is fixed is JDK 1.5 but not in Bea? SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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