there are rmi tests using TestLibrary.createRegistryOnUnusedPort, getUnusedRandomPort, registry created by these 2 methods could cause "port in use" exception intermittently. For some of the tests, these 2 methods can and should be replaced with createRegistryOnEphemeralPort and getRegistryPort.
Although not all the modified tests failed, it will help improve rmi test quality by replacing these methods.