After ARROW-3191 [1], consumers of Arrow Java with a JDK 9 and above are required to set the JVM property "io.netty.tryReflectionSetAccessible=true" at startup, each time Arrow code is run, as documented at [2]. Not doing this will result in the error "java.lang.UnsupportedOperationException: sun.misc.Unsafe or java.nio.DirectByteBuffer.(long, int) not available". This is due to a part of the Netty codebase, and I'm not sure if there any way around it, but I don't think it's the correct behavior for Arrow out-of-the-box to fail with a 3rd party error by default. This has come up before in our own unit testing [3], and most recently when upgrading Arrow in Spark [4].
I'd like to propose that Arrow Java change to the following behavior: 1) check to see if the property io.netty.tryReflectionSetAccessible has been set 2) if not set, automatically set to "true" 3) else if set to "false", catch the Netty error and prepend the error message with the suggested setting of "true" What do other devs think? [1] https://issues.apache.org/jira/browse/ARROW-3191 [2] https://github.com/apache/arrow/tree/master/java#java-properties [3] https://issues.apache.org/jira/browse/ARROW-5412 [4] https://github.com/apache/spark/pull/26552
