Getting the error while integrating stanford sentiment analysis with java

Question

I am working on sentiment analysis using stanford sentiment nlp library with java. But when I am executing the code I am getting the error. Not able to figure it out.

My code is as follows:

package com.nlp;

 import java.util.Properties;
 import edu.stanford.nlp.ling.CoreAnnotations;
 import edu.stanford.nlp.pipeline.Annotation;
 import edu.stanford.nlp.pipeline.StanfordCoreNLP;
 import edu.stanford.nlp.rnn.RNNCoreAnnotations;
 import edu.stanford.nlp.sentiment.SentimentCoreAnnotations;
 import edu.stanford.nlp.trees.Tree;
 import edu.stanford.nlp.util.CoreMap;

 public class SemanticAnalysis {
    public static void main(String args[]) {
        sentimentAnalysis sentiment = new sentimentAnalysis();
        sentiment.findSentiment("france is a good city");
    }   
 }

 class sentimentAnalysis {
     public String findSentiment(String line) {

        Properties props = new Properties();
        props.setProperty("annotators", "tokenize, ssplit, parse, sentiment");
        StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
        int mainSentiment = 0;
        if (line != null && line.length() > 0) {
            int longest = 0;
            Annotation annotation = pipeline.process(line);
           for (CoreMap sentence :annotation.get( CoreAnnotations.SentencesAnnotation.class )) {
                Tree tree = sentence.get(SentimentCoreAnnotations.AnnotatedTree.class);
                int sentiment = RNNCoreAnnotations.getPredictedClass(tree);
                String partText = sentence.toString();
                if (partText.length() > longest) {
                    mainSentiment = sentiment;
                    longest = partText.length();
                } 
            }
        }
        if (mainSentiment == 2 || mainSentiment > 4 || mainSentiment < 0) {
            return null;
        }
        return "";
     }
 }

But when i am running the code i am getting the following error.

   Exception in thread "main" java.lang.NoClassDefFoundError: org/ejml/simple/SimpleBase
at edu.stanford.nlp.pipeline.SentimentAnnotator.<init>(SentimentAnnotator.java:45)
at edu.stanford.nlp.pipeline.StanfordCoreNLP$14.create(StanfordCoreNLP.java:845)
at edu.stanford.nlp.pipeline.AnnotatorPool.get(AnnotatorPool.java:81)  

Answer 1

You are missing the ejml-0.23.jar, add it to your class path and it should work.

Answer 2

You are missing the reference to Efficient Java Matrix Library (EJML) in your classpath.

BTW. Try to split your code into smaller single task methods to get more clear code.

class SentimentAnalysis {

     public String findSentiment(String line) {

        if(line == null || line.isEmpty()) {
          throw new IllegalArgumentException("The line must not be null or empty.");
        }

        Annotation annotation = processLine(line);

        int mainSentiment = findMainSentiment(annotation);

        if(mainSentiment < 0 || mainSentiment == 2 || mainSentiment > 4) { //You should avoid magic numbers like 2 or 4 try to create a constant that will provide a description why 2
           return null; //You shold avoid null returns 
        }

        return "";

     }


     private int findMainSentiment(Annotation annotation) {

        int mainSentiment = Integer.MIN_VALUE;
        int longest = Integer.MIN_VALUE;


        for (CoreMap sentence : annotation.get(CoreAnnotations.SentencesAnnotation.class)) {

           int sentenceLength = String.valueOf(sentence).length();

           if(sentenceLength > longest) {

             Tree tree = sentence.get(SentimentCoreAnnotations.AnnotatedTree.class);

             mainSentiment = RNNCoreAnnotations.getPredictedClass(tree);

             longest = sentenceLength ;

            }
        }

        return mainSentiment;

     }


     private Annotation processLine(String line) {

        StanfordCoreNLP pipeline = createPieline();

        return pipeline.process(line);

     }

     private StanfordCoreNLP createPieline() {

        Properties props = createPipelineProperties();

        StanfordCoreNLP pipeline = new StanfordCoreNLP(props);

        return pipeline;

     }

     private Properties createPipelieProperties() {

        Properties props = new Properties();
        props.setProperty("annotators", "tokenize, ssplit, parse, sentiment");

        return props;

     }


 }