Hadoop: «ERROR : JAVA_HOME is not set»

Question

I'm trying to install Hadoop on Ubuntu 11.10. I set the JAVA_HOME variable in the file conf/hadoop-env.sh to:

# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

and then I execute these commands (Standalone Operation):

$ mkdir input 
$ cp conf/*.xml input 
$ bin/hadoop jar hadoop-examples-*.jar grep input output 'dfs[a-z.]+' 
$ cat output/*

but I have the following error when executing the third command:

ERROR : JAVA_HOME is not set

Is the JAVA_HOME variable not set correctly?

Answer 1

Make sure that you have removed the comment tag and changed your JAVA_HOME in the hadoop-env.sh as well as the appropriate .bashrc and/or .profile:

# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

should be

export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

You can set your JAVA_HOME and PATH for all users (make sure you haven't previously set this to the wrong path) in /etc/profile.

Also, don't forget to activate the new change by logging-out/in or by executing source /etc/profile.

Answer 2

You should set JAVA_HOME in the hadoop-env.sh file also which is in the Hadoop configuration directory. By default the JAVA_HOME setting line is commented.

Answer 3

Type echo $JAVA_HOME in your terminal to be sure your JAVA_HOME is set.

You can also type java -version to know what version of java you are actually using.

By the way, reading your description it seems your actually writing

export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

in the file conf/hadoop-env.sh, you should write it in your terminal or in ~/.bashrc or ~/.profile then type source < path to modified file >.

Answer 4

You can add in your .bashrc file:

export JAVA_HOME=$(readlink -f /usr/bin/java | sed "s:bin/java::")

and it will dynamically change when you update your packages.

Answer 5

Copy this export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk to hadoop-env.sh file.

JAVA_HOME is the location where java binaries are present.

Answer 6

The solution that worked for me was setting my JAVA_HOME in /etc/environment

Though JAVA_HOME can be set inside the /etc/profile files, the preferred location for JAVA_HOME or any system variable is /etc/environment.

Open /etc/environment in any text editor like nano or vim and add the following line:

JAVA_HOME="/usr/lib/jvm/your_java_directory"

Load the variables:

source /etc/environment

Check if the variable loaded correctly:

echo $JAVA_HOME

Answer 7

I tried the above solutions but the following worked on me

export JAVA_HOME=/usr/java/default

Answer 8

I solved this in my env, without modify hadoop-env.sh

You'd be better using /bin/bash as default shell not /bin/sh

Check these before:

1. You have already config java and env (success echo $JAVA_HOME)
2. right config hadoop

echo $SHELL in every node, check if print /bin/bash if not, vi /etc/passwd, add /bin/bash at tail of your username ref

Changing default shell in Linux

https://blog.csdn.net/whitehack/article/details/51705889

Answer 9

• hadoop ERROR : JAVA_HOME is not set

Above error is because of the space in between two words.

Eg: Java located in C:\Program Files\Java --> Space in between Program and files would cause the above problem. If you remove the space, it would not show any error.