how to add external jars to a class in rosjava hydro [closed]

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I am trying to modify the Listener.java class in rosjava_tutorial_pubsub to accept a word from a publisher in python and then pass this word to a classifier which is an external jar I want to add to my listener.java class. This is the modified code of the Listener.java:

package org.ros.rosjava_tutorial_pubsub;

import org.apache.commons.logging.Log;

import org.ros.message.MessageListener;

import org.ros.namespace.GraphName;

import org.ros.node.AbstractNodeMain;

import org.ros.node.ConnectedNode;

import org.ros.node.NodeMain;

import org.ros.node.topic.Subscriber;

public class Listener extends AbstractNodeMain {

@Override public GraphName getDefaultNodeName() { return GraphName.of("rosjava_tutorial_pubsub/listener"); }

@Override public void onStart(ConnectedNode connectedNode) { final Log log = connectedNode.getLog();

***final edu.uic.cs.nlp.ros.da.DaClassifier daClassifer = DaClassifier.getInstance();***

Subscriber<std_msgs.String> subscriber =        
connectedNode.newSubscriber("chatter", std_msgs.String._TYPE);
subscriber.addMessageListener(new MessageListener<std_msgs.String>() {
  @Override
  public void onNewMessage(std_msgs.String message) {

  ***java.lang.String da = daClassifer.classify(message.getData());

  log.info("output of the classifier: \"" + da + "\"");***
  }
});

} }

Where do I add the classifier's jar as a dependency? I put the jar in the build/install/rosjava_tutorial_pubsub/lib along with the rest of the jars of the package. I also added the following line to my build.gradle:

compile fileTree(dir: 'build/install/rosjava_tutorial_pubsub/lib', include: 'lin.jar')

Is this enough in ros hydro or do i need to make changes in my package.xml as well?