....

src/main/java/cn/com/qmth/examcloud/commons/helpers/concurrency/simple/ConcurrentTask.java

@@ -56,7 +56,11 @@ public class ConcurrentTask {
 	 * @return
 	 */
 	public boolean offerElement(Object e) {
-		return queue.offer(e);
+		boolean offer = queue.offer(e);
+		if (LOG.isDebugEnabled()) {
+			LOG.debug("offerElement. result=" + offer + ";element=" + e.toString());
+		}
+		return offer;
 	}
 
 	/**
@@ -141,6 +145,9 @@ public class ConcurrentTask {
 					}
 
 					try {
+						if (LOG.isDebugEnabled()) {
+							LOG.debug("process. element=" + el.toString());
+						}
 						worker.process(workerController, el);
 					} catch (Exception e) {
 						LOG.error("unexpected exception", e);