- Improve error-handling.

- Improve a log-message.

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

@@ -80,8 +80,11 @@ public class PublicationsRetrieverPlugin {
 
         File curAssignmentsDirs = new File(FileUtils.storeDocFilesDir);
         try {
-            if ( ! curAssignmentsDirs.mkdirs() ) // Create the subdirectory. It may return "false", in case it already exists (will not happen, unless there is problem in cleaning up of the subdirectories) or any problem occurred.
+            if ( !curAssignmentsDirs.exists() ) {
-                throw new RuntimeException("Could not create the \"assignments_" + assignmentRequestCounter + "_fullTexts\" directories: \"" + FileUtils.storeDocFilesDir + "\"!");
+                if ( !curAssignmentsDirs.mkdirs() ) // Try to create the directory(-ies) if they don't exist. If they exist OR if sth went wrong, the result is the same: "false".
+                    throw new RuntimeException("Could not create the \"" + currentAssignmentsSubDir + "\" directories: \"" + FileUtils.storeDocFilesDir + "\"!");
+            } else
+                logger.warn("The curAssignmentsDirs: \"" + currentAssignmentsSubDir + "\" already exist! Probably left behind by a previous execution..");
         } catch (Exception e) { // Mainly a SecurityException.
             throw new RuntimeException("Failed to create the full-texts directory for assignments_" + assignmentRequestCounter + ": " + e.getMessage());
         }

src/main/java/eu/openaire/urls_worker/controllers/GeneralController.java

@@ -66,7 +66,7 @@ public class GeneralController {
 
         String finalMsg = "";
         if ( shouldShutdownWorker )
-            finalMsg = "The worker has already received a \"shutdownWorker\" (which was not canceled afterwards). ";
+            finalMsg = "The worker has already received a \"shutdownWorker\" request (which was not canceled afterwards). ";
         else
             shouldShutdownWorker = true;