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Configuring HPCC for Java Integration

1. Download and Install the HPCC Systems platform with plugins 4.x

You will need the distro beginning with hpccsystems-platform_community-with-plugins-, NOT hpccsystems-platform_community-

You must install the packages that have the plug-ins using the --nodeps option. For example: sudo rpm -Uvh --nodeps <rpm file name>

Follow the installation instructions [here] for downloading HPCC & installing it. Specific instructions for installing the package with plugins are on page 17 of

2. Install OpenJDK 1.




some cases you may have to install the default-jdk package as well.

Check that Java Plugins are Working

  1. If you haven't run java on the cluster before, verify that Javaembed is functioning correctly on the cluster

    1. Run sample java like the following. JavaCat is installed on the HPCC Cluster by default.

Code Block
IMPORT java;
integer add1(integer val) := IMPORT(java, 'JavaCat.add1:(I)I');

If you get output, you have installed java successfully.

If you get a "unable to load" error you should reinstall java, or try a different Java package.

If you get an error about missing javaembed, the HPCC install does not include the plugin feature and needs to be reinstalled from a distro with the plugin feature.

Deploy your Java Jar File

  1. Verify that your java class was not compiled with a more recent version of java than is on the cluster.
    1. You can check this by running "rpm -qa|grep java" on one of the cluster nodes.

  2. Copy the Java jar or class file to all of the THOR nodes on a cluster.
    1. The default location for java files is /opt/HPCCSystems/classes.

    2. This can be done manually or by running something like:

      for x in `seq 8`;do scp myjava.jar 10.173.147.$x:/opt/HPCCSystems/classes/ ;done     done    


  3. Set the classpath in the HPCC Systems configuration file   

    1. By default you will find the configuration file located at The JAR file itself can be physically located anywhere. You can add the JAR file to the classpath by adding it to /etc/HPCCSystems/environment.conf, or by adding it to the Java global classpath environment variable.

    2. Edit the file environment.conf in your favorite editor and add your java class/jar to the classpath entry

      1. If you are adding a jar file, the jar file itself has to be added to the classpath. For example:




1. Place the Jar or class file on all of the THOR nodes in the cluster.

The default location for java files is /opt/HPCCSystems/classes.

3. Set the classpath in the HPCC Systems configuration file


4. Start the HPCC Systems Platform. I am running the platform on a single node for simplicity


Useful Commands:


  1. Restart the thor cluster for the classpath changes to take effect

sudo service hpcc-init start    => command for starting

sudo service hpcc-init stop     => command for stopping

sudo service hpcc-init restart  => command for restarting


5. Test if Java integration is working correctly

The HPCC Systems platform comes bundled with a Java example class.


Execute the following example in your favorite ECL IDE (or ECL Watch Playground)



Call your Java from ECL

Currently, you can only pass primitive data types to and from a Java plugin (String, long, etc.)

Define the interface for the java class you're calling. For example, if you're calling a static method SegmentText in the class Segmenter with the definition of  

      public static String SegmentText(String input, String config)
You would place the following code in your ecl:

import java;
      STRING segment() := IMPORT(java,







Feel free to raise an issue at if it does not work as expected. I assure you that it will be addressed promptly.