9 (test only) RFR: 8180279: java/net/httpclient/whitebox/Driver.java failed due to timeout

[Daniel Fuchs]

[sent by mistake to core-libs-dev, sorry for cross posting]

Hi,

Please find below a test-only fix for:

8180279: java/net/httpclient/whitebox/Driver.java failed due to timeout
https://bugs.openjdk.java.net/browse/JDK-8180279

The failing testcase is RawChannelTest.

The test appears to be failing because of a flaw in the test logic which
allowed for a race condition between the client and the (fake) server.

http://cr.openjdk.java.net/~dfuchs/webrev_8180279/webrev.00/

What can be seen from the traces is that when the test fails,
the client is writing bytes to the server and the server is
writing bytes to the client but the client never wakes up to read
the bytes. It can also be seen that the client has found some bytes
in the 'initialByteBuffer' of the RawChannel.

What happens here is that the initialRawBuffer has read all
the bytes that were available in the channel - and the server
is waiting for the client to stall before writing more bytes.
But the code that will unblock the server is never executed,
because it is triggered by a selector read event, and the
channel is already dry so the event is never fired.

I reworked the tests a bit, adding two new CountDownLatches to
ensure that 1. the client will always find initial bytes in the
channel's initialByteBuffer (the intermittent condition that made
the test fail) and 2. the server will wait for the client to
signal that it has got the initial bytes, and write an additional
chunk of bytes that will trigger the selector read (which will
in turn ensure that the client will unblock the server later on).

best regards,

-- daniel