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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=21224 race condition in LookupDispatchAction.execute Summary: race condition in LookupDispatchAction.execute Product: Struts Version: Nightly Build Platform: All OS/Version: Other Status: NEW Severity: Normal Priority: Other Component: Standard Actions AssignedTo: [EMAIL PROTECTED] ReportedBy: [EMAIL PROTECTED] This bug is in version 1.1 release. I found it by reading source code. I did not reproduce it, because it is a race condition, potentially very hard to reproduce. The race condition may occur if - two HTTP requests are serviced concurrently - both requests use the same locale - both requests use an action based on LookupDispatchAction - LookupDispatchAction.localeMap does not contain yet a map for the locale in question The race condition should have the following effect: one of the HTTP requests will use an empty map for the reverse-mapping of the submit button value into a message key. To understand this, consider a concurrent execution on behalf of two HTTP requests of the following code. Assume that both requests use the same locale, and that LookupDispatchAction.localeMap does not contain yet a map for this locale: In method execute in LookupDispatchAction: 206 synchronized (localeMap) { 207 lookupMap = (Map) this.localeMap.get(userLocale); 208 if (lookupMap == null) { 209 newLookupMap = true; 210 lookupMap = new HashMap(); 211 this.localeMap.put(userLocale, lookupMap); 212 } 213 } - this critical section was first executed by HTTP request 1. This request found lookupMap == null, and therefore set newLookupMap = true, and inserted a new, empty HashMap into localeMap. - then, the critical section was executed by HTTP request 2. Because request 1 inserted an object into localeMap, at key userLocal, request 2 found lookupMap != null. As a result, for request 2 we have newLookupMap = false. The code continues as follows: 214 215 synchronized (lookupMap) { 216 if (newLookupMap) { <<< Here, we insert content into lookupMap >>> 245 } This critical section is first executed by request 2. lookupMap receives no content, because newLookupMap is empty. At this point, request 2 is ready to use an empty lookup map, and fail to dispatch the request to the relevant method. Voila, the race condition occured. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
