- Add handling for additional/specific exceptions, when checking the "futures".

- Move common "ExecutionException" handling-code into its own method: "GenericUtils.getSelectedStackTraceForCausedException()".
- Avoid a double log.
- Code polishing.

src/main/java/eu/openaire/urls_controller/components/ScheduledTasks.java

@@ -112,22 +112,16 @@ public class ScheduledTasks {
                 if ( ! future.get() )   // Get and see if an exception is thrown. This blocks the current thread, until the task of the future has finished.
                     numFailedTasks ++;
             } catch (ExecutionException ee) {   // These can be serious errors like an "out of memory exception" (Java HEAP).
-                // The stacktrace of the "ExecutionException" is the one of the current code and not the code which ran inside the background-task. Try to get the cause.
+                logger.error(GenericUtils.getSelectedStackTraceForCausedException(ee, "Background_task_" + i + " failed with: ", null, 30));
-                Throwable throwable = ee.getCause();
-                if ( throwable == null ) {
-                    logger.warn("No cause was retrieved for the \"ExecutionException\"!");
-                    throwable = ee;
-                }
-                logger.error(GenericUtils.getSelectiveStackTrace(throwable, "Background task_" + i + " failed with: " + throwable.getMessage(), 30));
                 numFailedTasks ++;
             } catch (CancellationException ce) {
-                logger.error("Background task_" + i + " was cancelled: " + ce.getMessage());
+                logger.error("Background_task_" + i + " was cancelled: " + ce.getMessage());
                 numFailedTasks ++;
             } catch (InterruptedException ie) {
-                logger.error("Background task_" + i + " was interrupted: " + ie.getMessage());
+                logger.error("Background_task_" + i + " was interrupted: " + ie.getMessage());
                 numFailedTasks ++;
             } catch (IndexOutOfBoundsException ioobe) {
-                logger.error("IOOBE for background task_" + i + " in the futures-list! " + ioobe.getMessage());
+                logger.error("IOOBE for background_task_" + i + " in the futures-list! " + ioobe.getMessage());
                 // Only here, the "future" will be null.
             } finally {
                 if ( future != null )   // It may be null in case we have a IOBE.

src/main/java/eu/openaire/urls_controller/services/BulkImportServiceImpl.java

@@ -164,18 +164,14 @@ public class BulkImportServiceImpl implements BulkImportService {
                     // In case all the files failed to be bulk-imported, then we will detect it in the "numSuccessfulSegments"-check later.
                     // The failed-to-be-imported files, will not be deleted, even if the user specifies that he wants to delete the directory.
                 } catch (ExecutionException ee) {   // These can be serious errors like an "out of memory exception" (Java HEAP).
-                    // The stacktrace of the "ExecutionException" is the one of the current code and not the code which ran inside the background-task. Try to get the cause.
-                    Throwable throwable = ee.getCause();
-                    if ( throwable == null ) {
-                        logger.warn("No cause was retrieved for the \"ExecutionException\"!");
-                        throwable = ee;
-                    }
-                    String stackTraceMessage = GenericUtils.getSelectiveStackTrace(throwable, "Task_" + i + " failed with: " + throwable.getMessage() + additionalLoggingMsg, 15);
                     numFailedSegments ++;
-                    logger.error("Task_" + i + " failed with: " + stackTraceMessage);
+                    logger.error(GenericUtils.getSelectedStackTraceForCausedException(ee, "Task_" + i + " failed with: ", additionalLoggingMsg, 15));
                 } catch (CancellationException ce) {
                     numFailedSegments ++;
                     logger.error("Task_" + i + " was cancelled: " + ce.getMessage() + additionalLoggingMsg);
+                } catch (InterruptedException ie) {
+                    numFailedSegments ++;
+                    logger.error("Task_" + i + " was interrupted: " + ie.getMessage());
                 } catch (IndexOutOfBoundsException ioobe) {
                     logger.error("IOOBE for task_" + i + " in the futures-list! " + ioobe.getMessage() + additionalLoggingMsg);
                 }

src/main/java/eu/openaire/urls_controller/util/GenericUtils.java

@@ -1,11 +1,16 @@
 package eu.openaire.urls_controller.util;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import javax.servlet.http.HttpServletRequest;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 
 public class GenericUtils {
 
+    private static final Logger logger = LoggerFactory.getLogger(GenericUtils.class);
+
 
     public static final String endOfLine = "\n";
 
@@ -22,6 +27,20 @@ public class GenericUtils {
     }
 
 
+
+    public static String getSelectedStackTraceForCausedException(Throwable thr, String firstMessage, String additionalMessage, int numOfLines)
+    {
+        // The stacktrace of the "ExecutionException" is the one of the current code and not the code which ran inside the background-task. Try to get the cause.
+        Throwable causedThrowable = thr.getCause();
+        if ( causedThrowable == null ) {
+            logger.warn("No cause was retrieved for the \"ExecutionException\"!");
+            causedThrowable = thr;
+        }
+        String initialMessage = firstMessage + causedThrowable.getMessage() + ((additionalMessage != null) ? additionalMessage : "");
+        return getSelectiveStackTrace(causedThrowable, initialMessage, numOfLines);
+    }
+
+
     public static String getSelectiveStackTrace(Throwable thr, String initialMessage, int numOfLines)
     {
         StackTraceElement[] stels = thr.getStackTrace();

src/main/java/eu/openaire/urls_controller/util/ParquetFileUtils.java

@@ -43,6 +43,7 @@ import java.util.ArrayList;
 import java.util.Base64;
 import java.util.List;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.stream.Collectors;
@@ -687,11 +688,11 @@ public class ParquetFileUtils {
         int numOfAllPayloadParquetFileCreations = 0;
         int numOfFailedPayloadParquetFileCreations = 0;
 
-        for ( Future<ParquetReport> future : futures )
+        int sizeOfFutures = futures.size();
+        for ( int i = 0; i < sizeOfFutures; ++i )
         {
-            ParquetReport parquetReport = null;
             try {
-                parquetReport = future.get();
+                ParquetReport parquetReport = futures.get(i).get();
                 boolean hasProblems = (! parquetReport.isSuccessful());
                 ParquetReport.ParquetType parquetType = parquetReport.getParquetType();
                 if ( parquetType.equals(ParquetReport.ParquetType.attempt) ) {
@@ -707,20 +708,17 @@ public class ParquetFileUtils {
                     logger.error(errMsg);
                     return new SumParquetSuccess(false, false, ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errMsg));
                 }
-            } catch (Exception e) {
+            } catch (ExecutionException ee) {   // These can be serious errors like an "out of memory exception" (Java HEAP).
-                Throwable throwable = e;
+                logger.error(GenericUtils.getSelectedStackTraceForCausedException(ee, "Parquet_task_" + i + " failed with: ", null, 15));
-                if ( e instanceof ExecutionException ) {
+            } catch (CancellationException ce) {
-                    // The stacktrace of the "ExecutionException" is the one of the current code and not the code which ran inside the background-task. Try to get the cause.
+                logger.error("Parquet_task_" + i + " was cancelled: " + ce.getMessage());
-                    throwable = e.getCause();
+            } catch (InterruptedException ie) {
-                    if ( throwable == null ) {
+                logger.error("Parquet_task_" + i + " was interrupted: " + ie.getMessage());
-                        logger.warn("No cause was retrieved for the \"ExecutionException\"!");
+            } catch (IndexOutOfBoundsException ioobe) {
-                        throwable = e;
+                logger.error("IOOBE for parquet_task_" + i + " in the futures-list! " + ioobe.getMessage());
-                    }
-                }
-                logger.error("", throwable);
-                // We do not know if the failed "future" refers to a "payload" or to a "attempt".
-                // So we cannot increase a specific counter. That's ok, the only drawback if that we may try to "load" the non-existent data and get an exception.
             }
+			// We do not know if the failed "future" refers to a "payload" or to a "attempt".
+            // So we cannot increase a specific counter. That's ok, the only drawback if that we may try to "load" the non-existent data and get an exception.
         }   // End-for
 
         boolean hasAttemptParquetFileProblem = (numOfFailedAttemptParquetFileCreations == numOfAllAttemptParquetFileCreations);