storke width is accessed only when it's set

converter-sbml/src/main/java/lcsb/mapviewer/converter/model/sbml/species/SbmlSpeciesParser.java

@@ -106,7 +106,7 @@ public class SbmlSpeciesParser extends SbmlElementParser<org.sbml.jsbml.Species>
   protected void applyStyleToElement(Element elementWithLayout, LocalStyle style) {
     super.applyStyleToElement(elementWithLayout, style);
     Species specisWithLayout = (Species) elementWithLayout;
-    if (style.getGroup().getStrokeWidth() != null) {
+    if (style.getGroup().isSetStrokeWidth()) {
       specisWithLayout.setLineWidth(style.getGroup().getStrokeWidth());
     }
   }