Introduction The first question is why are we installing an old JDK. The answer is that Oracle JDK 6.0 update 31 is the JDK recommended by Cloudera when installing CDH4 (Cloudera Distribution Hadoop v4). This is an update to an older version of this post. Mainly I have changed the JDK from 1.6.0_26 to 1.6.0_31 …