Correct dependency error

pom.xml

@@ -85,6 +85,13 @@
             <version>1.4</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.8.1</version>
+        </dependency>
+
+
         <dependency>
             <groupId>be.cylab</groupId>
             <artifactId>java-roc</artifactId>

src/main/java/be/cylab/java/wowa/training/Utils.java

@@ -247,6 +247,11 @@ public final class Utils {
         return true_alert;
     }
 
+    /**
+     * Function to convert a List of double to an Array of doubles.
+     * @param elements
+     * @return
+     */
     public static double[] convertListDoubleToArrayDouble(
             final List<Double> elements) {
         Double[] w = new Double[elements.size()];