diff --git a/src/main/java/eu/omp/irap/vespa/epntapclient/utils/Queries.java b/src/main/java/eu/omp/irap/vespa/epntapclient/utils/Queries.java
index dc4473c..24f534b 100644
--- a/src/main/java/eu/omp/irap/vespa/epntapclient/utils/Queries.java
+++ b/src/main/java/eu/omp/irap/vespa/epntapclient/utils/Queries.java
@@ -69,7 +69,7 @@ public final class Queries {
 				addJoin.add(param.getKey() + " = " + param.getValue().toString());
 			}
 		}
-		String where = "".equals(addJoin) ? "" : " WHERE " + addJoin;
+		String where = "".equals(addJoin.toString()) ? "" : " WHERE " + addJoin;
 		return "SELECT TOP " + nbRow + " target_name, target_class FROM " + tableName + where;
 	}
 
--
libgit2 0.21.2