@SdkInternalApi
    final GetBlockResult executeGetBlock(GetBlockRequest getBlockRequest) {

        ExecutionContext executionContext = createExecutionContext(getBlockRequest);
        AWSRequestMetrics awsRequestMetrics = executionContext.getAwsRequestMetrics();
        awsRequestMetrics.startEvent(Field.ClientExecuteTime);
        Request<GetBlockRequest> request = null;
        Response<GetBlockResult> response = null;

        try {
            awsRequestMetrics.startEvent(Field.RequestMarshallTime);
            try {
                request = new GetBlockRequestProtocolMarshaller(protocolFactory).marshall(super.beforeMarshalling(getBlockRequest));
                // 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, "QLDB");
                request.addHandlerContext(HandlerContextKey.OPERATION_NAME, "GetBlock");
                request.addHandlerContext(HandlerContextKey.ADVANCED_CONFIG, advancedConfig);

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

            HttpResponseHandler<AmazonWebServiceResponse<GetBlockResult>> responseHandler = protocolFactory.createResponseHandler(new JsonOperationMetadata()
                    .withPayloadJson(true).withHasStreamingSuccessResponse(false), new GetBlockResultJsonUnmarshaller());
            response = invoke(request, responseHandler, executionContext);

            return response.getAwsResponse();

        } finally {

            endClientExecution(awsRequestMetrics, request, response);
        }
    }
<p>
Returns a block object at a specified address in a journal. Also returns a proof of the specified block for
verification if <code>DigestTipAddress</code> is provided.
</p>
<p>
For information about the data contents in a block, see <a
href="https://docs.aws.amazon.com/qldb/latest/developerguide/journal-contents.html">Journal contents</a> in the
<i>Amazon QLDB Developer Guide</i>.
</p>
<p>
If the specified ledger doesn't exist or is in <code>DELETING</code> status, then throws
<code>ResourceNotFoundException</code>.
</p>
<p>
If the specified ledger is in <code>CREATING</code> status, then throws
<code>ResourcePreconditionNotMetException</code>.
</p>
<p>
If no block exists with the specified address, then throws <code>InvalidParameterException</code>.
</p>

@param getBlockRequest
@return Result of the GetBlock operation returned by the service.
@throws InvalidParameterException
        One or more parameters in the request aren't valid.
@throws ResourceNotFoundException
        The specified resource doesn't exist.
@throws ResourcePreconditionNotMetException
        The operation failed because a condition wasn't satisfied in advance.
@sample AmazonQLDB.GetBlock
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/qldb-2019-01-02/GetBlock" target="_top">AWS API
     Documentation</a>
aws-java-sdk-qldb/src/main/java/com/amazonaws/services/qldb/AmazonQLDBClient.java