copy line only if not null

model/src/main/java/lcsb/mapviewer/model/map/reaction/Reaction.java

@@ -288,7 +288,9 @@ public class Reaction implements BioEntity {
       throw new InvalidReactionParticipantNumberException(new ElementUtils().getElementTag(original)
           + "Invalid source reaction: number of reactants must be at least " + minReactants);
     }
-    line = new PolylineData(original.getLine());
+    if (original.getLine() != null) {
+      line = new PolylineData(original.getLine());
+    }
   }
 
   public Reaction(String reactionId) {
@@ -406,10 +408,10 @@ public class Reaction implements BioEntity {
   /**
    * Return list of all lines in the reaction that describe it.
    * 
-   * @return list of all lines that describes every connection in the rection
+   * @return list of all lines that describes every connection in the reaction
    */
   public List<Line2D> getLines() {
-    List<Line2D> result = new ArrayList<Line2D>();
+    List<Line2D> result = new ArrayList<>();
     for (AbstractNode node : nodes) {
       result.addAll(node.getLine().getLines());
     }