[ https://issues.jboss.org/browse/JGRP-1688?page=com.atlassian.jira.plugin.... ] shen kim commented on JGRP-1688: -------------------------------- For Example: I declared Callable implement like this: public class CustomerCallback implements Callable<String> { ... } Then, I used it in following step: 1,ExecutionCompletionService<String> execService = new ExecutionCompletionService<String>(new ExecutionService(this.channel)); 2,Class<CustomerCallback> clazz = CustomerCallback.class; 3,Constructor<CustomerCallback> cc = clazz.getConstructor(new Class[]{}); 4,execService.submit(Executions.serializableCallable(cc, new Object[]{})); In step 4, the IDE would tip me: The method submit(Callable<String>) in the type ExecutionCompletionService<String> is not applicable for the arguments (Callable<capture#1-of ?>) -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira