public void setETag(String etag) {
        this.eTag = etag;
    }
Sets the entity tag identifying the new object. An entity tag is an
opaque string that changes if and only if an object's data changes.

@param etag
           The entity tag.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/transfer/model/UploadResult.java