public void setReactionUsers(java.util.Collection<String> reactionUsers) {
        if (reactionUsers == null) {
            this.reactionUsers = null;
            return;
        }

        this.reactionUsers = new java.util.ArrayList<String>(reactionUsers);
    }
<p>
The Amazon Resource Names (ARNs) of users who have provided reactions to the comment.
</p>

@param reactionUsers
       The Amazon Resource Names (ARNs) of users who have provided reactions to the comment.
aws-java-sdk-codecommit/src/main/java/com/amazonaws/services/codecommit/model/ReactionForComment.java