Hi, In June there was a discussion about the problem synchronization in FilterToBeanProxy, which results in a change in this class: Now the method doInit() is synchronized.
But this dosn't solve the problem: When the first thread starts executing doInit() it sets initialized to true. If a second thread gets running before the first thread ends with doInit() the second thread detects "initialized is true" and runs in the same NullPointerException, because "delegate" is still null. The reason is, that the test "if (!initialized)" isn't synchronized. I see two solutions for this problem: 1.) Add a method isInitialized(), which is synchronized too and replace "if (!initialized)" by "if (!isInitialized())". The ugly point in this solution is, that this synchronization has to take place in the startup phase of a webapp, but we don't need it after the initialization has finished. But a synchronized isInitialized() would synchronize each request to this webapp. 2.) Place the statement "initialized = true;" at the end of doInit(). The advantage of this solution would be that synchronization would be done in startup phase only. The problem of this solution is, that you can't be sure, that on every machine the concurrency solution works (see the "Double Checked Locking" problem, e.g. http://en.wikipedia.org/wiki/Double-checked_locking <http://en.wikipedia.org/wiki/Double-checked_locking> ). But I think that this solution should be ok, because "initialized" is a primitive type (no object) and because the synchronization is only needed for startup time, which is normally an issue while development, not after real deployment. So I would suggest to choose solution 2.). Regards Volker Gruß Volker _________________________ Volker Malzahn FJA Feilmeier & Junker GmbH Ein Unternehmen der FJH Gruppe Sachsenring 83 50677 Köln Tel.: 0221 / 33 80 - 271 Fax: 0221 / 9 32 17 30 Email: [EMAIL PROTECTED] ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ Home: http://acegisecurity.sourceforge.net Acegisecurity-developer mailing list Acegisecurity-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acegisecurity-developer
