I want to know what java versions are compatible with the latest hadoop. The most that the documentation <https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/ClusterSetup.html#Prerequisites> says is to check the wiki <https://cwiki.apache.org/confluence/display/HADOOP2/HadoopJavaVersions>, which is obviously out of date since it only is listing java 6 and 7. That wiki has a link to another wiki page <https://cwiki.apache.org/confluence/display/HADOOP/Hadoop+Java+Versions>, which is more helpful, as it actually lists the compatible versions of java. However, it doesn't say which jdk's/jvm's are supported (Oracle vs OpenJDK, vs AdoptOpenJDK, or hotspot vs open-j9). Also, that page says that hadoop 3 is only compatible with java 8, but Cloudera's CDH 6, which uses <https://docs.cloudera.com/documentation/enterprise/6/release-notes/topics/rg_cdh_63_packaging.html#cdh_632_packaging> hadoop 3, apparently supports <https://docs.cloudera.com/documentation/enterprise/6/release-notes/topics/rg_java_requirements.html#concept_ugf_4sg_5gb> openjdk11.
We would really like to use java 11 with our new hadoop builds due to the improved garbage collection, and would also prefer to use non-oracle jdk builds, but the messaging about what is supported seems sparse and sometimes contradictory. Any clarification would be appreciated. Thanks! - Augustine
