OO-2048: fix autoboxing of boolean value which can be null

src/main/java/org/olat/course/nodes/ta/DropboxForm.java

@@ -77,7 +77,8 @@ public class DropboxForm extends FormBasicController {
 	protected void formOK(UserRequest ureq) {
 		fireEvent (ureq, Event.DONE_EVENT);
 	}
-	
+
+	@Override
 	protected void formInnerEvent (UserRequest ureq, FormItem source, FormEvent event) {
 		if (source == enablemail) {
 			confirmation.setMandatory (enablemail.isSelected(0));
@@ -112,7 +113,9 @@ public class DropboxForm extends FormBasicController {
 		confirmation = uifactory.addTextAreaElement("confirmation", "form.dropbox.confirmation", 2500, 4, 40, true, sConfirmation != null ? sConfirmation : "", formLayout);
 		
 		Boolean enableMail = (Boolean)config.get(TACourseNode.CONF_DROPBOX_ENABLEMAIL);
-		confirmation.setMandatory(enableMail);
+		if(enableMail != null) {
+			confirmation.setMandatory(enableMail.booleanValue());
+		}
 		enablemail = uifactory.addCheckboxesHorizontal("enablemail", "form.dropbox.enablemail", formLayout, new String[]{"xx"}, new String[]{null});
 		enablemail.select("xx", enableMail != null ? enableMail.booleanValue() : true);
 		enablemail.addActionListener(FormEvent.ONCLICK);