Setting the Runtime Java Environment
The version of Java used to compile REEF is controlled in the Maven pom.xml file in the build plugins section under the maven-compiler-plugin artifact identifier. In order to run REEF applications, you must set the JAVA_HOME environment variable to the correct Java installation directory for your operating system and java version.
On a number of Linux distributions such as Ubuntu, the current active version of Java is controlled via links from /usr/bin set by the update-alternatives command; thus, the value of JAVA_HOME that causes REEF to use the Java version controlled by update-alternatives is given in the code block below. REEF will concatenate the appropriate path to find executable files.
You can change the active version of Java controlled by update-alternatives by entering the command below and selecting the desired version from the displayed list.
Test Environment Configuration
The REEF unit tests require a large number of simultaneously open files to successfully complete. This may or may not be allowed by your platform administrator.
The default number of open files in an Ubuntu shell is 1024. You can verify this by typing the following command at the shell prompt.
If you have sudo privileges, you can temporarily increase the number of open files by starting a shell as root, increasing the limit, and then starting a new shell with your login name.
A more permanent fix requires changing values in system files. If the following lines exist in the /etc/security/limits.conf file, update them to a size of at least 40960. If these line do not exist, add them to the end of the file.
If the following line does not exist in the /etc/pam.d/common-session file, add it.
Reboot your machine.
Now type "ulimit -n" at the shell prompt and you should get return a value of 40960 which should be sufficient to run the REEF unit tests.