Had the great fun of digging through this one. Had a user reporting that hiveserver2 was no longer finding HBase jars on the classpath. This is supposed to happen via hbase mapredcp.
It turned out that they had configured hive-env.sh to set HADOOP_CLIENT_OPTS="-XX:+PrintGCDetails" (among other things), which creates a big multi-line string instead of just a directory. Because of poor quoting in bin/hbase, this gives you a wonderfully intuitive error:
That Heap is actually from the JVM GC details that it was told to print. While I don't expect this to be a common problem people run into, it's one that we can address with better quoting. e.g.