- Reduce the "PublicationsRetriever.threadsMultiplier" to 4.

- Eliminate a possible NPE.

src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java

@@ -52,7 +52,7 @@ public class PublicationsRetrieverPlugin {
         ConnSupportUtils.shouldBlockMost5XXDomains = false;
         LoaderAndChecker.setCouldRetryRegex();
 
-        PublicationsRetriever.threadsMultiplier = 6;
+        PublicationsRetriever.threadsMultiplier = 4;
         int workerThreadsCount = Runtime.getRuntime().availableProcessors() * PublicationsRetriever.threadsMultiplier;
         logger.info("Use " + workerThreadsCount + " worker-threads.");
         PublicationsRetriever.executor = Executors.newFixedThreadPool(workerThreadsCount);
@@ -157,7 +157,7 @@ public class PublicationsRetrieverPlugin {
                     //logger.debug("initialId: " + initialId);    // DEBUG!
                     // Search that ID inside the list and if that instance gave the docUrl (there might be multiple ID instances) then get the file-location.
                     for ( DataToBeLogged data_2 : FileUtils.dataToBeLoggedList ) {
-                        if ( data_2.getUrlId().equals(initialId) && data_2.getWasDocumentOrDatasetAccessible().equals("true") ) {
+                        if ( data_2.getUrlId().equals(initialId) && ("true".equals(data_2.getWasDocumentOrDatasetAccessible())) ) {
                             fileLocation = data_2.getComment();
                             size = data_2.getSize();
                             hash = data_2.getHash();