public void setExternalId(String externalId) {
        this.externalId = externalId;
    }
<p>
(Deprecated) Your AWS account ID, which you assigned to an external ID key in an IAM trust policy. Amazon
Pinpoint previously used this value to assume an IAM role when importing endpoint definitions, but we removed
this requirement. We don't recommend use of external IDs for IAM roles that are assumed by Amazon Pinpoint.
</p>

@param externalId
       (Deprecated) Your AWS account ID, which you assigned to an external ID key in an IAM trust policy. Amazon
       Pinpoint previously used this value to assume an IAM role when importing endpoint definitions, but we
       removed this requirement. We don't recommend use of external IDs for IAM roles that are assumed by Amazon
       Pinpoint.
aws-java-sdk-pinpoint/src/main/java/com/amazonaws/services/pinpoint/model/SegmentImportResource.java