Problem with empty classname in classloader ------------------------------------------- Key: JBAS-3265 URL: http://jira.jboss.com/jira/browse/JBAS-3265 Project: JBoss Application Server Issue Type: Bug Security Level: Public(Everyone can see) Components: JMX Affects Versions: JBossAS-4.0.4.GA Reporter: Adrian Brock Assigned To: Scott M Stark Fix For: JBossAS-5.0.0.Beta2, JBossAS-4.2.0.CR1 The RepositoryClassLoader doesn't handle empty classnames correctly. It eventually breaks when it tries to do the array name handling here: // If this is an array class, use Class.forName to resolve it if( name.charAt(0) == '[' ) { result = Class.forName(name, true, this); removeFromClassBlackList(name); return result; } 17:04:42,858 ERROR [STDERR] java.lang.StringIndexOutOfBoundsException: String index out of range: 0 17:04:42,860 ERROR [STDERR] at java.lang.String.charAt(String.java:444) 17:04:42,861 ERROR [STDERR] at org.jboss.mx.loading.RepositoryClassLoader.loadClassLocally(RepositoryClassLoader.java:169) 17:04:42,862 ERROR [STDERR] at org.jboss.mx.loading.UnifiedLoaderRepository3.loadClassFromClassLoader(UnifiedLoaderRepository3.java:263) 17:04:42,862 ERROR [STDERR] at org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:270) 17:04:42,864 ERROR [STDERR] at org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(RepositoryClassLoader.java:475) 17:04:42,865 ERROR [STDERR] at org.jboss.mx.loading.RepositoryClassLoader.loadClass(RepositoryClassLoader.java:377) 17:04:42,865 ERROR [STDERR] at java.lang.ClassLoader.loadClass(ClassLoader.java:235) The classloader should just reject a null or empty ("") classname in loadClass() with a meaningful error message. I suspect the null is handled by the cache since the cache is a Concurrent HashMap which won't accept null as a key.