public void setCreationDateTime(java.util.Date creationDateTime) {
        this.creationDateTime = creationDateTime;
    }
<p>
The date/time the instance group was created.
</p>

@param creationDateTime
       The date/time the instance group was created.
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/InstanceGroupDetail.java