https://issues.apache.org/bugzilla/show_bug.cgi?id=44041
--- Comment #9 from Richard George <rcgeorg...@gmail.com> 2009-05-12 08:58:56 PST --- (In reply to comment #8) Hi, We also experienced this issue while using the Sysdeo plugin with DevLoader. It was resolved (for us) by synchronizing WebappClassLoader.loadClass. Cheers. > Are you sure it is OK to synchronize around the call to > URLClassLoader.findClass? > > If you have a page with 2 frames, each loading a JSP at the same time: > > Thread T1 tries to load my.class.Foo > Thread T2 tries to load my.class.Foo > > T1 calls WebappClassLoader.loadClass > T2 calls WebappClassLoader.loadClass > > WebappClassLoader determines it has not loaded the class for both threads > (since there is no synchronization at this point). > > Both T1 and T2 get to the synchronized block in findClass. > They get synchronized, but doing the wrong thing, and a LinkageError gets > thrown. > > Don't you think that WebappClassLoader.loadClass(String, boolean) ought to be > synchronized just like it is in java.lang.ClassLoader? > > I am actually running into this problem with Tomcat 5.5.27 (on a 4 core > machine): > > Caused by: java.lang.LinkageError: loader (instance of > org/apache/catalina/loader/WebappClassLoader): attempted duplicate class > definition for name: "org/apache/struts/taglib/tiles/PutTag" > at java.lang.ClassLoader.defineClass1(Native Method) > at java.lang.ClassLoader.defineClass(ClassLoader.java:621) > at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) > at java.net.URLClassLoader.defineClass(URLClassLoader.java:260) > at java.net.URLClassLoader.access$000(URLClassLoader.java:56) > at java.net.URLClassLoader$1.run(URLClassLoader.java:195) > at java.security.AccessController.doPrivileged(Native Method) > at java.net.URLClassLoader.findClass(URLClassLoader.java:188) > at > org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:904) > at > org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1353) > at > org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1232) > at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:125) > at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:63) > at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) > .... etc .... -- Configure bugmail: https://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
