修改了注册接口

src/test/java/com/greenorange/promotion/list/ListTest.java

@@ -0,0 +1,32 @@
+package com.greenorange.promotion.list;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ListTest {
+    public static void main(String[] args) {
+        List<Node> list = new ArrayList<>();
+        list.add(new Node(1));
+        list.add(new Node(2));
+        list.add(new Node(3));
+        for (Node node : list) {
+            System.out.println(node.val);
+        }
+        for (Node node : list) {
+            node.setVal(1);
+        }
+        for (Node node : list) {
+            System.out.println(node.val);
+        }
+    }
+}
+
+class Node {
+    int val;
+    public Node(int val) {
+        this.val = val;
+    }
+    public void setVal(int val) {
+        this.val = val;
+    }
+}