# Java Bindings: CreatedEvent and ExercisedEvent: witnessParties is a List\<String\> vs signatories/observers is Set\<String\>

**URL:** <https://forum.canton.network/t/java-bindings-createdevent-and-exercisedevent-witnessparties-is-a-list-string-vs-signatories-observers-is-set-string/4910>\
**Category:** App Development\
**Created:** [July 14, 2022, 8:53pm UTC](https://forum.canton.network/t/java-bindings-createdevent-and-exercisedevent-witnessparties-is-a-list-string-vs-signatories-observers-is-set-string/4910 "2022-07-14T20:53:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![StephenOTT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/stephenott/32/3953_2.png) [@StephenOTT](https://forum.canton.network/u/StephenOTT)\
**Post date:** [July 14, 2022, 8:53pm UTC](https://forum.canton.network/t/java-bindings-createdevent-and-exercisedevent-witnessparties-is-a-list-string-vs-signatories-observers-is-set-string/4910/1 "2022-07-14T20:53:33Z")

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Noticing that in the java bindings there is the witnessParties List vs the signatories and observer fields are Set

```java
public final class CreatedEvent implements Event, TreeEvent {
    private final @NonNull List<@NonNull String> witnessParties;
    private final String eventId;
    private final Identifier templateId;
    private final String contractId;
    private final DamlRecord arguments;
    private final Optional<String> agreementText;
    private final Optional<Value> contractKey;
    private final @NonNull Set<@NonNull String> signatories;
    private final @NonNull Set<@NonNull String> observers;
...

```

Is there a scenario where witnessParties would have duplicates or the order of the parties in the list is an indicator of something?

Thanks

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<div class="post-metadata">

**Author:** ![cocreature](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/cocreature/32/36_2.png) [@cocreature](https://forum.canton.network/u/cocreature)\
**Post date:** [July 15, 2022, 6:41am UTC](https://forum.canton.network/t/java-bindings-createdevent-and-exercisedevent-witnessparties-is-a-list-string-vs-signatories-observers-is-set-string/4910/2 "2022-07-15T06:41:05Z")

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There is no reason for this being a list, it could also be a set.

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<div class="post-metadata">

**Author:** ![StephenOTT](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/stephenott/32/3953_2.png) [@StephenOTT](https://forum.canton.network/u/StephenOTT)\
**Post date:** [July 15, 2022, 12:02pm UTC](https://forum.canton.network/t/java-bindings-createdevent-and-exercisedevent-witnessparties-is-a-list-string-vs-signatories-observers-is-set-string/4910/3 "2022-07-15T12:02:50Z")

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Thanks!