Working With Hadoop: localhost: Error: JAVA_HOME is not set

Question

I\'m working with Ubuntu 12.04 LTS.

I\'m going through the hadoop quickstart manual to make a pseudo-distributed operation. It seems simple and straightforward (eas

Answer 1

The way to debug this is to put an "echo $JAVA_HOME" in start-all.sh. Are you running your hadoop environment under a different username, or as yourself? If the former, it's very likely that the JAVA_HOME environment variable is not set for that user.

The other potential problem is that you have specified JAVA_HOME incorrectly, and the value that you have provided doesn't point to a JDK/JRE. Note that "which java" and "java -version" will both work, even if JAVA_HOME is set incorrectly.