public java.util.List<String> getReadReplicaDBClusterIdentifiers() {
        if (readReplicaDBClusterIdentifiers == null) {
            readReplicaDBClusterIdentifiers = new com.amazonaws.internal.SdkInternalList<String>();
        }
        return readReplicaDBClusterIdentifiers;
    }
<p>
The identifiers of Aurora DB clusters to which the RDS DB instance is replicated as a read replica. For example,
when you create an Aurora read replica of an RDS for MySQL DB instance, the Aurora MySQL DB cluster for the
Aurora read replica is shown. This output doesn't contain information about cross-Region Aurora read replicas.
</p>
<note>
<p>
Currently, each RDS DB instance can have only one Aurora read replica.
</p>
</note>

@return The identifiers of Aurora DB clusters to which the RDS DB instance is replicated as a read replica. For
        example, when you create an Aurora read replica of an RDS for MySQL DB instance, the Aurora MySQL DB
        cluster for the Aurora read replica is shown. This output doesn't contain information about cross-Region
        Aurora read replicas.</p> <note>
        <p>
        Currently, each RDS DB instance can have only one Aurora read replica.
        </p>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/model/DBInstance.java