Olaf Flebbe, Tom Zeng, Jonathan Kelly
I've just updated BIGTOP-1561
At this point, JAVA_HOME on bigtop_toolchain should point out Java version 7 and as Olaf described, installed OpenJDK8 and env variable JAVA8_HOME are required as well due to the requirement Java8u40+ for building Presto.
From the PR, I removed hard-coded JAVA_HOME. now, scripts and wrappers just validate version number from 'java -version'. that being said, 'java' command from the PATH will be used for running Presto. I believe that way is convenient for users.