Occasionally, the MultiThreadTest.java server receives 6 valid connections instead of the expected 5. It seems that from time to time the client might drop one connection (usually connection 0) and create a sixth one. Why this is happening is unclear and should be investigated. In the mean time and for the sake of test stability, MultiThreadTest.java is updated by
JDK-8223716 to accept `thread + 1` connections - and just report it as a warning.