# Amazon SQS Java SDK examples
The AWS SDK for Java allows you build Java applications that interact with Amazon SQS and other AWS services.
+ To install and set up the SDK, see [Getting started](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/getting-started.html) in the *AWS SDK for Java 2.x Developer Guide*.
+ For basic queue operations—such as creating a queue or sending a message—see [ Working with Amazon SQS Message Queues](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/sqs-examples.html) in the *AWS SDK for Java 2.x Developer Guide*.
+ This guide also includes examples of additional Amazon SQS features, such as:
+ [Using server-side encryption with Amazon SQS queues](sqs-java-configure-sse.md)
+ [Configuring tags for an Amazon SQS queue](sqs-java-add-update-remove-tag-queue.md)
+ [Sending message attributes to an Amazon SQS queue](sqs-java-send-message-with-attributes.md)
# Using server-side encryption with Amazon SQS queues
Use the AWS SDK for Java to add server-side encryption (SSE) to an Amazon SQS queue. Each queue uses an AWS Key Management Service (AWS KMS) KMS key to generate the data encryption keys. This example uses the AWS managed KMS key for Amazon SQS.
For more information about using SSE and the role of the KMS key, see [Encryption at rest in Amazon SQS](sqs-server-side-encryption.md).
## Adding SSE to an existing queue
To enable server-side encryption for an existing queue, use the `[SetQueueAttributes](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_SetQueueAttributes.html)` method to set the `KmsMasterKeyId` attribute.
The following code example sets the AWS KMS key as the AWS managed KMS key for Amazon SQS. The example also sets the [AWS KMS key reuse period](sqs-server-side-encryption.md#sqs-sse-key-terms) to 140 seconds.
Before you run the example code, make sure that you have set your AWS credentials. For more information, see [Set up AWS Credentials and Region for Development](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/setup.html#setup-credentials) in the *AWS SDK for Java 2.x Developer Guide*.
```
public static void addEncryption(String queueName, String kmsMasterKeyAlias) {
SqsClient sqsClient = SqsClient.create();
GetQueueUrlRequest urlRequest = GetQueueUrlRequest.builder()
.queueName(queueName)
.build();
GetQueueUrlResponse getQueueUrlResponse;
try {
getQueueUrlResponse = sqsClient.getQueueUrl(urlRequest);
} catch (QueueDoesNotExistException e) {
LOGGER.error(e.getMessage(), e);
throw new RuntimeException(e);
}
String queueUrl = getQueueUrlResponse.queueUrl();
Map attributes = Map.of(
QueueAttributeName.KMS_MASTER_KEY_ID, kmsMasterKeyAlias,
QueueAttributeName.KMS_DATA_KEY_REUSE_PERIOD_SECONDS, "140" // Set the data key reuse period to 140 seconds.
); // This is how long SQS can reuse the data key before requesting a new one from KMS.
SetQueueAttributesRequest attRequest = SetQueueAttributesRequest.builder()
.queueUrl(queueUrl)
.attributes(attributes)
.build();
try {
sqsClient.setQueueAttributes(attRequest);
LOGGER.info("The attributes have been applied to {}", queueName);
} catch (InvalidAttributeNameException | InvalidAttributeValueException e) {
LOGGER.error(e.getMessage(), e);
throw new RuntimeException(e);
} finally {
sqsClient.close();
}
}
```
## Disabling SSE for a queue
To disable server-side encryption for an existing queue, set the `KmsMasterKeyId` attribute to an empty string using the `SetQueueAttributes` method.
**Important**
`null` isn't a valid value for `KmsMasterKeyId`.
## Creating a queue with SSE
To enable SSE when you create the queue, add the `KmsMasterKeyId` attribute to the `[CreateQueue](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_CreateQueue.html)` API method.
The following example creates a new queue with SSE enabled. The queue uses the AWS managed KMS key for Amazon SQS. The example also sets the [AWS KMS key reuse period](sqs-server-side-encryption.md#sqs-sse-key-terms) to 160 seconds.
Before you run the example code, make sure that you have set your AWS credentials. For more information, see [Set up AWS Credentials and Region for Development](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/setup.html#setup-credentials) in the *AWS SDK for Java 2.x Developer Guide*.
```
// Create an SqsClient for the specified Region.
SqsClient sqsClient = SqsClient.builder().region(Region.US_WEST_1).build();
// Create a hashmap for the attributes. Add the key alias and reuse period to the hashmap.
HashMap attributes = new HashMap();
final String kmsMasterKeyAlias = "alias/aws/sqs"; // the alias of the AWS managed KMS key for Amazon SQS.
attributes.put(QueueAttributeName.KMS_MASTER_KEY_ID, kmsMasterKeyAlias);
attributes.put(QueueAttributeName.KMS_DATA_KEY_REUSE_PERIOD_SECONDS, "140");
// Add the attributes to the CreateQueueRequest.
CreateQueueRequest createQueueRequest =
CreateQueueRequest.builder()
.queueName(queueName)
.attributes(attributes)
.build();
sqsClient.createQueue(createQueueRequest);
```
## Retrieving SSE attributes
For information about retrieving queue attributes, see [Examples](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_GetQueueAttributes.html#API_GetQueueAttributes_Examples) in the *Amazon Simple Queue Service API Reference*.
To retrieve the KMS key ID or the data key reuse period for a particular queue, run the `[GetQueueAttributes](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_GetQueueAttributes.html)` method and retrieve the `KmsMasterKeyId` and `KmsDataKeyReusePeriodSeconds` values.
# Configuring tags for an Amazon SQS queue
Use cost-allocation tags to help organize and identify your Amazon SQS queues. The following examples show how to configure tags using the AWS SDK for Java. For more information, see [Amazon SQS cost allocation tags](sqs-queue-tags.md).
Before you run the example code, make sure that you have set your AWS credentials. For more information, see [Set up AWS Credentials and Region for Development](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/setup.html#setup-credentials) in the *AWS SDK for Java 2.x Developer Guide*.
## Listing tags
To list the tags for a queue, use the `ListQueueTags` method.
```
// Create an SqsClient for the specified region.
SqsClient sqsClient = SqsClient.builder().region(Region.US_WEST_1).build();
// Get the queue URL.
String queueName = "MyStandardQ1";
GetQueueUrlResponse getQueueUrlResponse =
sqsClient.getQueueUrl(GetQueueUrlRequest.builder().queueName(queueName).build());
String queueUrl = getQueueUrlResponse.queueUrl();
// Create the ListQueueTagsRequest.
final ListQueueTagsRequest listQueueTagsRequest =
ListQueueTagsRequest.builder().queueUrl(queueUrl).build();
// Retrieve the list of queue tags and print them.
final ListQueueTagsResponse listQueueTagsResponse =
sqsClient.listQueueTags(listQueueTagsRequest);
System.out.println(String.format("ListQueueTags: \tTags for queue %s are %s.\n",
queueName, listQueueTagsResponse.tags() ));
```
## Adding or updating tags
To add or update tag values for a queue, use the `TagQueue` method.
```
// Create an SqsClient for the specified Region.
SqsClient sqsClient = SqsClient.builder().region(Region.US_WEST_1).build();
// Get the queue URL.
String queueName = "MyStandardQ1";
GetQueueUrlResponse getQueueUrlResponse =
sqsClient.getQueueUrl(GetQueueUrlRequest.builder().queueName(queueName).build());
String queueUrl = getQueueUrlResponse.queueUrl();
// Build a hashmap of the tags.
final HashMap addedTags = new HashMap<>();
addedTags.put("Team", "Development");
addedTags.put("Priority", "Beta");
addedTags.put("Accounting ID", "456def");
//Create the TagQueueRequest and add them to the queue.
final TagQueueRequest tagQueueRequest = TagQueueRequest.builder()
.queueUrl(queueUrl)
.tags(addedTags)
.build();
sqsClient.tagQueue(tagQueueRequest);
```
## Removing tags
To remove one or more tags from the queue, use the `UntagQueue` method. The following example removes the `Accounting ID` tag.
```
// Create the UntagQueueRequest.
final UntagQueueRequest untagQueueRequest = UntagQueueRequest.builder()
.queueUrl(queueUrl)
.tagKeys("Accounting ID")
.build();
// Remove the tag from this queue.
sqsClient.untagQueue(untagQueueRequest);
```
# Sending message attributes to an Amazon SQS queue
You can include structured metadata (such as timestamps, geospatial data, signatures, and identifiers) with messages using *message attributes*. For more information, see [Amazon SQS message attributes](sqs-message-metadata.md#sqs-message-attributes).
Before you run the example code, make sure that you have set your AWS credentials. For more information, see [Set up AWS Credentials and Region for Development](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/setup.html#setup-credentials) in the *AWS SDK for Java 2.x Developer Guide*.
## Defining attributes
To define an attribute for a message, add the following code, which uses the `[MessageAttributeValue](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_MessageAttributeValue.html)` data type. For more information, see [Message attribute components](sqs-message-metadata.md#message-attribute-components) and [Message attribute data types](sqs-message-metadata.md#message-attribute-data-types).
The AWS SDK for Java automatically calculates the message body and message attribute checksums and compares them with the data that Amazon SQS returns. For more information, see the *[AWS SDK for Java 2.x Developer Guide](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/)* and [Calculating the MD5 message digest for message attributes](sqs-message-metadata.md#sqs-attributes-md5-message-digest-calculation) for other programming languages.
------
#### [ String ]
This example defines a `String` attribute named `Name` with the value `Jane`.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("Name", new MessageAttributeValue()
.withDataType("String")
.withStringValue("Jane"));
```
------
#### [ Number ]
This example defines a `Number` attribute named `AccurateWeight` with the value `230.000000000000000001`.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("AccurateWeight", new MessageAttributeValue()
.withDataType("Number")
.withStringValue("230.000000000000000001"));
```
------
#### [ Binary ]
This example defines a `Binary` attribute named `ByteArray` with the value of an uninitialized 10-byte array.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("ByteArray", new MessageAttributeValue()
.withDataType("Binary")
.withBinaryValue(ByteBuffer.wrap(new byte[10])));
```
------
#### [ String (custom) ]
This example defines the custom attribute `String.EmployeeId` named `EmployeeId` with the value `ABC123456`.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("EmployeeId", new MessageAttributeValue()
.withDataType("String.EmployeeId")
.withStringValue("ABC123456"));
```
------
#### [ Number (custom) ]
This example defines the custom attribute `Number.AccountId` named `AccountId` with the value `000123456`.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("AccountId", new MessageAttributeValue()
.withDataType("Number.AccountId")
.withStringValue("000123456"));
```
**Note**
Because the base data type is `Number`, the `[ReceiveMessage](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ReceiveMessage.html)` method returns `123456`.
------
#### [ Binary (custom) ]
This example defines the custom attribute `Binary.JPEG` named `ApplicationIcon` with the value of an uninitialized 10-byte array.
```
final Map messageAttributes = new HashMap<>();
messageAttributes.put("ApplicationIcon", new MessageAttributeValue()
.withDataType("Binary.JPEG")
.withBinaryValue(ByteBuffer.wrap(new byte[10])));
```
------
## Sending a message with attributes
This example adds the attributes to the `SendMessageRequest` before sending the message.
```
// Send a message with an attribute.
final SendMessageRequest sendMessageRequest = new SendMessageRequest();
sendMessageRequest.withMessageBody("This is my message text.");
sendMessageRequest.withQueueUrl(myQueueUrl);
sendMessageRequest.withMessageAttributes(messageAttributes);
sqs.sendMessage(sendMessageRequest);
```
**Important**
If you send a message to a First-In-First-Out (FIFO) queue, make sure that the `sendMessage` method executes *after* you provide the message group ID.
If you use the `[SendMessageBatch](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_SendMessageBatch.html)` method instead of `[SendMessage](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_SendMessage.html)`, you must specify message attributes for each message in the batch.