refs #21 Added 'final' as per Kazuki's suggestion.

Author: harawata

src/main/java/org/apache/ibatis/scripting/xmltags/SetSqlNode.java

@@ -25,7 +25,7 @@
  */
 public class SetSqlNode extends TrimSqlNode {
 
-  private static List<String> COMMA = Collections.singletonList(",");
+  private static final List<String> COMMA = Collections.singletonList(",");
 
   public SetSqlNode(Configuration configuration,SqlNode contents) {
     super(configuration, contents, "SET", COMMA, null, COMMA);