Github user suez1224 commented on a diff in the pull request:
https://github.com/apache/flink/pull/4585#discussion_r140159053
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/aggfunctions/CollectAggFunction.scala
---
@@ -0,0 +1,121 @@
+/*
+ * 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.flink.table.functions.aggfunctions
+
+import java.lang.{Iterable => JIterable}
+import java.util
+import java.util.function.BiFunction
+
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.java.tuple.{Tuple1 => JTuple1}
+import org.apache.flink.api.java.typeutils.{GenericTypeInfo, TupleTypeInfo}
+import org.apache.flink.table.functions.AggregateFunction
+
+import scala.collection.JavaConverters._
+
+/** The initial accumulator for Collect aggregate function */
+class CollectAccumulator[E] extends JTuple1[util.Map[E, Integer]]
--- End diff --
Please take another look, I've updated to use MapView.
---
