MarkerComparator.saveState: fix ArrayIndexOutOfBoundsException

as logged during UiTestSuite

Author: EcljpseB0T

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerComparator.java

@@ -187,7 +187,9 @@ void restore(IMemento memento) {
 	 * Save the current sort field in the memento.
 	 */
 	void saveState(IMemento memento) {
-		memento.putString(PRIMARY_SORT_FIELD_TAG, MarkerSupportInternalUtilities.getId(fields[0]));
+		if (fields != null && fields.length > 0) {
+			memento.putString(PRIMARY_SORT_FIELD_TAG, MarkerSupportInternalUtilities.getId(fields[0]));
+		}
 		Iterator<MarkerField> descendingIterator = descendingFields.iterator();
 		while (descendingIterator.hasNext()) {
 			memento.createChild(DESCENDING_FIELDS, (MarkerSupportInternalUtilities.getId(descendingIterator.next())));