[ https://issues.jboss.org/browse/DROOLS-890?page=com.atlassian.jira.plugin... ] Thomas Leung commented on DROOLS-890: ------------------------------------- We did build from Drools source on 6.2.0.Final with the change following your provided link https://github.com/droolsjbpm/drools/commit/183518527. Basically it mainly synchronize the method public synchronized Class<?> defineClass(String name, String resourceName, byte[] bytecode). However, the same deadlock issue still happened while we run a load test again. This deadlock happened always when we run load test during the past couple of weeks. We noticed that everytime it locked at the below line in ProjectClassLoader.java: protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException { try { return loadType(name, resolve); } catch (ClassNotFoundException cnfe) { synchronized(projectClassLoader) { try { return projectClassLoader.internalLoadClass(name, resolve); <== wait for lock projectClassLoader object } catch (ClassNotFoundException cnfe2) { return projectClassLoader.tryDefineType(name, cnfe); } } } } That means it throws ClassNotFoundException in loadType(name, resolve). Is it an expected exception in normal usage or it happened abnormally? -- This message was sent by Atlassian JIRA (v6.4.11#64026)