...

src/main/java/cn/com/qmth/examcloud/commons/util/ThreadLocalUtil.java

@@ -113,6 +113,9 @@ public class ThreadLocalUtil {
 	 * @author WANGWEI
 	 */
 	public static void clearAll() {
-		LOCAL_TRACE_MAP.get().clear();
+		Map<String, Object> map = LOCAL_TRACE_MAP.get();
+		if (null != map) {
+			map.clear();
+		}
 	}
 }