X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fdatamodel%2FAlignment.java;h=91b29dab36366a690ae14c900592638e4e135ea0;hb=51ca42a8c4525c6871e3c8ea529b6cb8a59bb10f;hp=b214934a34263fb33fbf9aaa36a2b81102619e81;hpb=04e88679fd837e9fe36d186e5eacdd5f13a89927;p=jalview.git

diff --git a/src/jalview/datamodel/Alignment.java b/src/jalview/datamodel/Alignment.java
index b214934..91b29da 100755
--- a/src/jalview/datamodel/Alignment.java
+++ b/src/jalview/datamodel/Alignment.java
@@ -398,6 +398,10 @@ public class Alignment implements AlignmentI
     return null;
   }
 
+  private static final SequenceGroup[] noGroups = new SequenceGroup[0];
+
+  private ArrayList<SequenceGroup> temp = new ArrayList<>();
+
   /*
    * (non-Javadoc)
    * 
@@ -407,11 +411,15 @@ public class Alignment implements AlignmentI
   @Override
   public SequenceGroup[] findAllGroups(SequenceI s)
   {
-    ArrayList<SequenceGroup> temp = new ArrayList<>();
 
     synchronized (groups)
     {
+      temp.clear();
       int gSize = groups.size();
+      if (gSize == 0)
+      {
+        return noGroups;
+      }
       for (int i = 0; i < gSize; i++)
       {
         SequenceGroup sg = groups.get(i);