在Ubuntu中设置Java变量

Question

I am trying to install Amazon Mturk command line tool on Ubuntu 13.10 ( 32-bit) system.

After setting the access secrete and access identifier in mturk.properties file, I ran the getBalance.sh file and below is the output.

./getBalance.sh
You must set JAVA_HOME (i.e. export JAVA_HOME=/usr)
If you do not have JAVA on your machine, you can download it from http://java.sun.com/
./../bin/invoke.sh: 41: exit: Illegal number: -1

The following is the java information on my system

$ file `which java javac`
/usr/bin/java:  symbolic link to `/etc/alternatives/java'
/usr/bin/javac: symbolic link to `/etc/alternatives/javac'

My shell information is :

$ echo $SHELL
/bin/bash

But, $JAVA_HOME command gave me a blank line as result.

I can see the java installed on my machine :

$ which java
/usr/bin/java

$ java -version
java version "1.7.0_55"
OpenJDK Runtime Environment (IcedTea 2.4.7) (7u55-2.4.7-1ubuntu1~0.13.10.1)
OpenJDK Server VM (build 24.51-b03, mixed mode)

Then I ran the following commands:

$ export JAVA_HOME=/usr/bin/java
$ echo $JAVA_HOME
/usr/bin/java

I thought everything is correct now, but here is what I get if I run the getBalnace.sh

$ ./getBalance.sh 
./../bin/invoke.sh: 79: exec: /usr/bin/java/bin/java: not found

I checked my environment variables, below is the result

$ env | grep java
JAVA_HOME=/usr/bin/java
NODE_PATH=/usr/lib/nodejs:/usr/lib/node_modules:/usr/share/javascript

And the path is:

$ echo $PATH
/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/sid/.rvm/bin

I still could not figure out where am I doing wrong. The sentences below are quite confusing and no much information is available.

• If you downloaded the Unix distribution, you must set the MTURK_CMD_HOME environment variable to point to your Command Line Tools installation location.
• If you downloaded the Unix distribution, you must set the JAVA_HOME environment variable to point to your Java Standard Edition Runtime Environment (JRE) installation location.

Any help would be much appreciated.

Answer 1

In the Java world, JAVA_HOME refers to the directory where the JDK or JRE was installed. So you should be able to find the java executable at

$JAVA_HOME/bin/java

In your case, find the physical location where java is installed. Something like this should work:

readlink -f /usr/bin/javac

A typical response would be

/usr/lib/jvm/java-7-openjdk-amd64/bin/javac

For this response, you should set JAVA_HOME to

/usr/lib/jvm/java-7-openjdk-amd64