Index: lams_learning/src/java/org/lamsfoundation/lams/learning/web/util/LearningWebUtil.java
===================================================================
diff -u -r8aded0b18a5a7712622ae56f38923fa297449977 -rbe48a755dd63857599487663be908aa200adbaa6
--- lams_learning/src/java/org/lamsfoundation/lams/learning/web/util/LearningWebUtil.java	(.../LearningWebUtil.java)	(revision 8aded0b18a5a7712622ae56f38923fa297449977)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/web/util/LearningWebUtil.java	(.../LearningWebUtil.java)	(revision be48a755dd63857599487663be908aa200adbaa6)
@@ -50,7 +50,7 @@
 import org.lamsfoundation.lams.util.WebUtil;
 import org.lamsfoundation.lams.web.session.SessionManager;
 import org.lamsfoundation.lams.web.util.AttributeNames;
-import org.springframework.dao.CannotAcquireLockException;
+import org.springframework.dao.DataAccessException;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.context.support.WebApplicationContextUtils;
 
@@ -69,6 +69,8 @@
     // ---------------------------------------------------------------------
     public static final String PARAM_PROGRESS_ID = "progressID";
 
+    private static final int COMPLETE_ACTIVITY_MAX_ATTEMPTS = 3;
+
     // public static final String POPUP_WINDOW_NAME = "LearnerActivity";
     // public static final String LEARNER_WINDOW_NAME = "lWindow";
 
@@ -225,19 +227,7 @@
 	} else if (progress.getCompletedActivities().containsKey(currentActivity)) {
 	    return actionMappings.getCloseForward(currentActivity, lesson.getLessonId());
 	} else {
-	    // Set activity as complete; synchronized and repeated because of deadlock exceptions
-	    try {
-		progress = learnerService.completeActivity(learnerId, currentActivity, progress);
-	    } catch (CannotAcquireLockException e) {
-		LearningWebUtil.log.warn("Can not acquire lock to complete activity " + currentActivity.getActivityId()
-			+ " by learner " + learnerId + ". Retrying...");
-		try {
-		    Thread.sleep(2000);
-		} catch (InterruptedException e1) {
-		    // do nothing, it does not hurt us...
-		}
-		progress = learnerService.completeActivity(learnerId, currentActivity, progress);
-	    }
+	    progress = LearningWebUtil.completeActivity(learnerService, learnerId, progress, currentActivity, 1);
 	}
 
 	if ((currentActivity != null) && currentActivity.isFloating()) {
@@ -416,4 +406,30 @@
 	}
 	return positionDTO;
     }
+
+    /**
+     * Tries to complete the activity for the learner. Because of concurrency problems (deadlocks, indexes when
+     * inserting) the operation can fail and the easiet recovery is to repeat it.
+     */
+    private static LearnerProgress completeActivity(ICoreLearnerService learnerService, Integer learnerId,
+	    LearnerProgress progress, Activity currentActivity, int attempt) {
+	try {
+	    progress = learnerService.completeActivity(learnerId, currentActivity, progress);
+	} catch (DataAccessException e) {
+	    attempt++;
+	    StringBuilder message = new StringBuilder("Could not complete activity due to a data access exception.");
+	    if (attempt <= LearningWebUtil.COMPLETE_ACTIVITY_MAX_ATTEMPTS) {
+		message.append("Retrying. Attempt #").append(attempt).append(". The exception was: ")
+			.append(e.getMessage());
+		LearningWebUtil.log.warn(message.toString());
+		LearningWebUtil.completeActivity(learnerService, learnerId, progress, currentActivity, attempt);
+	    } else {
+		message.append("Reached limit of retries: " + LearningWebUtil.COMPLETE_ACTIVITY_MAX_ATTEMPTS);
+		LearningWebUtil.log.warn(message.toString());
+		throw e;
+	    }
+	}
+
+	return progress;
+    }
 }
\ No newline at end of file