@SdkInternalApi
    final ValidDBInstanceModificationsMessage executeDescribeValidDBInstanceModifications(
            DescribeValidDBInstanceModificationsRequest describeValidDBInstanceModificationsRequest) {

        ExecutionContext executionContext = createExecutionContext(describeValidDBInstanceModificationsRequest);
        AWSRequestMetrics awsRequestMetrics = executionContext.getAwsRequestMetrics();
        awsRequestMetrics.startEvent(Field.ClientExecuteTime);
        Request<DescribeValidDBInstanceModificationsRequest> request = null;
        Response<ValidDBInstanceModificationsMessage> response = null;

        try {
            awsRequestMetrics.startEvent(Field.RequestMarshallTime);
            try {
                request = new DescribeValidDBInstanceModificationsRequestMarshaller().marshall(super
                        .beforeMarshalling(describeValidDBInstanceModificationsRequest));
                // Binds the request metrics to the current request.
                request.setAWSRequestMetrics(awsRequestMetrics);
                request.addHandlerContext(HandlerContextKey.CLIENT_ENDPOINT, endpoint);
                request.addHandlerContext(HandlerContextKey.ENDPOINT_OVERRIDDEN, isEndpointOverridden());
                request.addHandlerContext(HandlerContextKey.SIGNING_REGION, getSigningRegion());
                request.addHandlerContext(HandlerContextKey.SERVICE_ID, "RDS");
                request.addHandlerContext(HandlerContextKey.OPERATION_NAME, "DescribeValidDBInstanceModifications");
                request.addHandlerContext(HandlerContextKey.ADVANCED_CONFIG, advancedConfig);

            } finally {
                awsRequestMetrics.endEvent(Field.RequestMarshallTime);
            }

            StaxResponseHandler<ValidDBInstanceModificationsMessage> responseHandler = new StaxResponseHandler<ValidDBInstanceModificationsMessage>(
                    new ValidDBInstanceModificationsMessageStaxUnmarshaller());

            response = invoke(request, responseHandler, executionContext);

            return response.getAwsResponse();

        } finally {

            endClientExecution(awsRequestMetrics, request, response);
        }
    }
<p>
You can call <code>DescribeValidDBInstanceModifications</code> to learn what modifications you can make to your
DB instance. You can use this information when you call <code>ModifyDBInstance</code>.
</p>
<p>
This command doesn't apply to RDS Custom.
</p>

@param describeValidDBInstanceModificationsRequest
@return Result of the DescribeValidDBInstanceModifications operation returned by the service.
@throws DBInstanceNotFoundException
        <code>DBInstanceIdentifier</code> doesn't refer to an existing DB instance.
@throws InvalidDBInstanceStateException
        The DB instance isn't in a valid state.
@sample AmazonRDS.DescribeValidDBInstanceModifications
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/rds-2014-10-31/DescribeValidDBInstanceModifications"
     target="_top">AWS API Documentation</a>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/AmazonRDSClient.java