fix: implement comments from mr

oaipmh-core/src/main/java/info/textgrid/middleware/OaipmhUtilities.java

@@ -155,18 +155,22 @@ public class OaipmhUtilities {
 
     log.fine("original DateTimeString: " + originalDateTimeString);
 
+    Instant instant;
     try {
       OffsetDateTime odt = OffsetDateTime.parse(originalDateTimeString);
-      result = UTC_FORMATTER.format(Instant.from(odt));
+      instant = Instant.from(odt);
     }
 
-    // TODO We are missing to set time zones on dcterms date fields!! Workaround for all DARIAH-DE
-    // Repository dates so far is using LocalDateTime here!
+    // NOTE We are missing to set time zones on dcterms date fields in administrative metadata!
+    // Workaround for all DARIAH-DE Repository dates so far (until fix) is using LocalDateTime here
+    // with ZoneId CET, what has been local time zone until now!
     catch (DateTimeParseException e) {
       LocalDateTime ldt = LocalDateTime.parse(originalDateTimeString);
-      result = UTC_FORMATTER.format(ldt.atZone(ZoneId.systemDefault()).toInstant());
+      instant = ldt.atZone(ZoneId.of("CET")).toInstant();
     }
 
+    result = UTC_FORMATTER.format(instant);
+
     log.fine("parsed to UTC: " + result);
 
     return result;