Hey all, tl;dr; I built Spark with Java 1.8 even though my JAVA_HOME pointed to 1.7. Then it failed with binary incompatibilities.
I couldn’t find any mention of this in the docs, so It might be a known thing, but it’s definitely too easy to do the wrong thing. The problem is that Maven is using the Zinc incremental compiler, which is a long-running server. If the first build (that spawns the zinc server) is started with Java 8 on the path, Maven will compile against Java 8 even after changing JAVA_HOME and rebuilding. I filed scala-maven-plugin#173 <https://github.com/davidB/scala-maven-plugin/issues/173> but so far no comment. Steps to reproduce: - make sure zinc is not running yet - build with JAVA_HOME pointing to 1.8 - point JAVA_HOME to 1.7 - clean build - run Spark, watch it fail with NoSuchMethodError in ConcurrentHashMap. More details here <https://gist.github.com/AlainODea/1375759b8720a3f9f094> Workaround: - build/zinc/bin/zinc -shutdown - rebuild iulian -- -- Iulian Dragos ------ Reactive Apps on the JVM www.typesafe.com