...

src/main/java/cn/com/qmth/examcloud/commons/helpers/pipeline/SimpleNode.java

@@ -136,7 +136,7 @@ public class SimpleNode<KEYIN, VALUEIN, KEYOUT, VALUEOUT>
 				}
 			}
 
-			if (removable.get()) {
+			if (null != removable.get() && removable.get()) {
 				if (null != key) {
 					getStorer().remove(key);
 				}