Github user franz1981 commented on a diff in the pull request:
https://github.com/apache/activemq-artemis/pull/2490#discussion_r246321398
--- Diff:
artemis-commons/src/main/java/org/apache/activemq/artemis/utils/collections/MultiIterator.java
---
@@ -0,0 +1,78 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.activemq.artemis.utils.collections;
+
+import java.util.Iterator;
+
+/**
+ * Provides an Iterator that works over multiple underlying iterators.
+ *
+ * @param <T> type of the class of the iterator.
+ */
+public class MultiIterator<T> implements Iterator<T> {
--- End diff --
`MultiIterator<I extends Iterator<T>, T> implements Iterator<T>`
It should avoid casting on children while manipulating `iterators` type
---
