There are streams opened but not closed in CXFConsumerImpl class, https://github.com/jbossws/jbossws-cxf/blob/master/modules/client/src/main/java/org/jboss/wsf/stack/cxf/tools/CXFConsumerImpl.java#L344-L362

The fix is to use try-with-resources as jbossws-cxf already targets Java 1.8 at minimum.