Class loading problem with XAResource and XADataSource ------------------------------------------------------ Key: WFCORE-561 URL: https://issues.jboss.org/browse/WFCORE-561 Project: WildFly Core Issue Type: Bug Components: Modules Reporter: David Lloyd Assignee: David Lloyd Fix For: 1.0.0.CR6, 2.0.0.Alpha3 We define the JTA API in a module ({{java.transaction.api}}) but we neglect to redefine those classes in the {{javax.sql}} package which reference that API, including {{XADataSource}}, which can cause {{LinkageError}} and strange CCEs under certain circumstances. The isolated subgraph of classes from that package need to be added to either the {{java.transaction.api}} module or a new {{javax.sql.api}} module. Then measures must be taken to prevent the JDK's version of these classes from leaking out, a task complicated by the presence of the rowset API classes also sharing that package. One solution is to ensure that the {{javax.api}} module includes a re-exported dependency on the module with the relocated classes which takes precedence over the system dependency, ensuring that the system classes never become visible. Another solution is to modify JBoss Modules to implement an XML mapping of the class filter concept, and then add class filter expressions to the {{module.xml}} of the {{javax.api}} module.