handle null values in TaxonNodeByRankAndNameComparator

diff --git a/cdmlib-model/src/main/java/eu/etaxonomy/cdm/compare/taxon/TaxonNodeByRankAndNameComparator.java b/cdmlib-model/src/main/java/eu/etaxonomy/cdm/compare/taxon/TaxonNodeByRankAndNameComparator.java
index a34438f4159508c44ba3888041cf702cc67f596e..755dbff1f4cbc6accdbae5a79b8ed6009fe3192c 100644 (file)
--- a/cdmlib-model/src/main/java/eu/etaxonomy/cdm/compare/taxon/TaxonNodeByRankAndNameComparator.java
+++ b/cdmlib-model/src/main/java/eu/etaxonomy/cdm/compare/taxon/TaxonNodeByRankAndNameComparator.java
@@ -27,6 +27,13 @@ public class TaxonNodeByRankAndNameComparator extends TaxonNodeByNameComparator
 
        @Override
     public int compare(TaxonNode node1, TaxonNode node2) {
+        if (node1 == null && node2 == null) {
+            return 0;
+        } else if (node1 == null) {
+            return 1;
+        } else if (node2 == null) {
+            return -1;
+        }
 
            boolean node1Excluded = node1.isExcluded();
         boolean node2Excluded = node2.isExcluded();