RFR: 8140241: (fc) Data transfer from FileChannel to itself causes hang in case of overlap

[Brian Burkhalter]

On Tue, 10 Aug 2021 01:21:21 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> This request proposes to fix a failure on macOS which occurs when transferring to or from a file channel from or to the same file channel when the source and destination intervals overlap.

This change would work around a bug specific to macOS which the operating system vendor has not fixed in more than five years. The JDK issue was filed in 2015 after having been observed on macOS 10.5.5 (Yosemite); the bug has been observed on macOS versions through 10.15.7 (Catalina).  

When run on macOS without the source fix, the included test hangs and its process cannot in general be killed without restarting or in some cases power cycling the machine.

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PR: https://git.openjdk.java.net/jdk/pull/5061