Github user zentol commented on a diff in the pull request: https://github.com/apache/flink/pull/4921#discussion_r148240608 --- Diff: flink-java/src/main/java/org/apache/flink/api/java/utils/ParameterTool.java --- @@ -560,9 +591,13 @@ protected Object clone() throws CloneNotSupportedException { * @return The Merged {@link ParameterTool} */ public ParameterTool mergeWith(ParameterTool other) { - ParameterTool ret = new ParameterTool(this.data); - ret.data.putAll(other.data); - ret.unrequestedParameters.addAll(other.unrequestedParameters); + Map<String, String> resultData = new HashMap<>(data.size() + other.data.size()); + resultData.putAll(data); + resultData.putAll(other.data); + + ParameterTool ret = new ParameterTool(resultData); + + ret.unrequestedParameters.putAll(other.unrequestedParameters); --- End diff -- what about `this.unrequestedParameters`?
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