DTLS tests fail intermittently with too much loops or timeout

 javax/net/ssl/DTLS/PacketLossRetransmission.java failed with following error message:

Server: =======handshake(0, NEED_UNWRAP)=======
Server: Receive DTLS records, handshake status is NEED_UNWRAP
Client: New handshake status is NEED_UNWRAP
Exception in ClientCallable.call():
java.lang.RuntimeException: Too much loops to produce handshake packets
at DTLSOverDatagram.handshake(DTLSOverDatagram.java:154)
at DTLSOverDatagram.doClientSide(DTLSOverDatagram.java:117)
at DTLSOverDatagram$ClientCallable.call(DTLSOverDatagram.java:681)
at DTLSOverDatagram$ClientCallable.call(DTLSOverDatagram.java:664)
at java.util.concurrent.FutureTask.run(java.base@9-internal/FutureTask.java:264)
at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@9-internal/ThreadPoolExecutor.java:1161)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@9-internal/ThreadPoolExecutor.java:635)
at java.lang.Thread.run(java.base@9-internal/Thread.java:844)
Exception on client side:
java.util.concurrent.ExecutionException: java.lang.RuntimeException: Too much loops to produce handshake packets
at java.util.concurrent.FutureTask.report(java.base@9-internal/FutureTask.java:122)
at java.util.concurrent.FutureTask.get(java.base@9-internal/FutureTask.java:191)
at DTLSOverDatagram.runTest(DTLSOverDatagram.java:602)
at PacketLossRetransmission.main(PacketLossRetransmission.java:89)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:537)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:110)
at java.lang.Thread.run(java.base@9-internal/Thread.java:844)
Caused by: java.lang.RuntimeException: Too much loops to produce handshake packets
at DTLSOverDatagram.handshake(DTLSOverDatagram.java:154)
at DTLSOverDatagram.doClientSide(DTLSOverDatagram.java:117)
at DTLSOverDatagram$ClientCallable.call(DTLSOverDatagram.java:681)
at DTLSOverDatagram$ClientCallable.call(DTLSOverDatagram.java:664)
at java.util.concurrent.FutureTask.run(java.base@9-internal/FutureTask.java:264)
at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@9-internal/ThreadPoolExecutor.java:1161)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@9-internal/ThreadPoolExecutor.java:635)
... 1 more
Server: Warning: java.net.SocketTimeoutException: Receive timed out
Server: New handshake status is NEED_UNWRAP
Server: Handshake finished, status is NEED_UNWRAP
Server: Negotiated protocol is NONE
Server: Negotiated cipher suite is SSL_NULL_WITH_NULL_NULL
Exception in ServerCallable.call():
java.lang.Exception: Unexpected handshake status NEED_UNWRAP
at DTLSOverDatagram.handshake(DTLSOverDatagram.java:286)
at DTLSOverDatagram.doServerSide(DTLSOverDatagram.java:98)
at DTLSOverDatagram$ServerCallable.call(DTLSOverDatagram.java:643)
at DTLSOverDatagram$ServerCallable.call(DTLSOverDatagram.java:626)
at java.util.concurrent.FutureTask.run(java.base@9-internal/FutureTask.java:264)
at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@9-internal/ThreadPoolExecutor.java:1161)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@9-internal/ThreadPoolExecutor.java:635)
at java.lang.Thread.run(java.base@9-internal/Thread.java:844)
Exception on server side:
java.util.concurrent.ExecutionException: java.lang.Exception: Unexpected handshake status NEED_UNWRAP
at java.util.concurrent.FutureTask.report(java.base@9-internal/FutureTask.java:122)
at java.util.concurrent.FutureTask.get(java.base@9-internal/FutureTask.java:191)
at DTLSOverDatagram.runTest(DTLSOverDatagram.java:612)
at PacketLossRetransmission.main(PacketLossRetransmission.java:89)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:537)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:110)
at java.lang.Thread.run(java.base@9-internal/Thread.java:844)
Caused by: java.lang.Exception: Unexpected handshake status NEED_UNWRAP
at DTLSOverDatagram.handshake(DTLSOverDatagram.java:286)
at DTLSOverDatagram.doServerSide(DTLSOverDatagram.java:98)
at DTLSOverDatagram$ServerCallable.call(DTLSOverDatagram.java:643)
at DTLSOverDatagram$ServerCallable.call(DTLSOverDatagram.java:626)
at java.util.concurrent.FutureTask.run(java.base@9-internal/FutureTask.java:264)
at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@9-internal/ThreadPoolExecutor.java:1161)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@9-internal/ThreadPoolExecutor.java:635)
... 1 more
----------System.err:(14/908)----------
java.lang.RuntimeException: Test failed
at DTLSOverDatagram.runTest(DTLSOverDatagram.java:621)
at PacketLossRetransmission.main(PacketLossRetransmission.java:89)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:537)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:110)
at java.lang.Thread.run(java.base@9-internal/Thread.java:844)

JavaTest Message: Test threw exception: java.lang.RuntimeException: Test failed
JavaTest Message: shutting down test


see attached file for full log