BUG: toString() of UTCDateTime

src/main/java/caosdb/datetime/UTCDateTime.java

@@ -292,7 +292,7 @@ public class UTCDateTime implements Interval {
 
   @Override
   public String toString() {
-    throw new NullPointerException("toString method!!!");
+    return toDateTimeString(TimeZone.getDefault());
   }
 
   public static UTCDateTime UTCSeconds(final Long utcseconds, final Integer nanosecond) {