Fix for the broken "earliest date" (#9309)

src/main/java/edu/harvard/iq/dataverse/harvest/server/OAIRecordServiceBean.java

@@ -375,4 +375,16 @@ public List<OAIRecord> findDeletedOaiRecordsBySetName(String setName) {
         }
     }
 
+    public Instant getEarliestDate() {
+        String queryString = "SELECT min(r.lastUpdateTime) FROM OAIRecord r";
+        TypedQuery<Date> query = em.createQuery(queryString, Date.class);
+        Date retDate = query.getSingleResult();
+        if (retDate != null) {
+            return retDate.toInstant();
+        }
+
+        // if there are no records yet, return the default "now"
+        return new Date().toInstant();
+    }
+
 }

src/main/java/edu/harvard/iq/dataverse/harvest/server/web/servlet/OAIServlet.java

@@ -195,7 +195,9 @@ private RepositoryConfiguration createRepositoryConfiguration() {
         }
         // The admin email address associated with this installation: 
         // (Note: if the setting does not exist, we are going to assume that they
-        // have a reason not to want to advertise their email address. 
+        // have a reason not to want to configure their email address, if it is
+        // a developer's instance, for example; or a reason not to want to 
+        // advertise it to the world.) 
         InternetAddress systemEmailAddress = MailUtil.parseSystemAddress(settingsService.getValueForKey(SettingsServiceBean.Key.SystemEmail));
         String systemEmailLabel = systemEmailAddress != null ? systemEmailAddress.getAddress() : "donotreply@localhost";
 
@@ -207,15 +209,14 @@ private RepositoryConfiguration createRepositoryConfiguration() {
                 .withResumptionTokenFormat(new SimpleResumptionTokenFormat().withGranularity(Granularity.Second))
                 .withRepositoryName(repositoryName)
                 .withBaseUrl(systemConfig.getDataverseSiteUrl()+"/oai")
-                .withEarliestDate(Instant.EPOCH) // this is NOT something we really want to be doing, but this will be corrected once PR9316 is merged
+                .withEarliestDate(recordService.getEarliestDate())
                 .withMaxListIdentifiers(maxListIdentifiers)
                 .withMaxListSets(maxListSets)
                 .withMaxListRecords(maxListRecords)
                 .withDeleteMethod(DeletedRecord.TRANSIENT)
                 .withEnableMetadataAttributes(true)
                 .withRequireFromAfterEarliest(false)
-                .build();
-
+                .build();        
 
         return configuration; 
     }