# Java code examples
<a name="CodeSamples.Java"></a>

**Topics**
+ [Java: Setting your Amazon credentials](#CodeSamples.Java.Credentials)
+ [Java: Setting the Amazon Region and endpoint](#CodeSamples.Java.RegionAndEndpoint)

This Developer Guide contains Java code snippets and ready-to-run programs. You can find these code examples in the following sections:
+ [Working with items and attributes in DynamoDB](WorkingWithItems.md)
+ [Working with tables and data in DynamoDB](WorkingWithTables.md)
+ [Querying tables in DynamoDB](Query.md)
+ [Scanning tables in DynamoDB](Scan.md)
+ [Improving data access with secondary indexes in DynamoDB](SecondaryIndexes.md)
+ [Java 1.x: DynamoDBMapper](DynamoDBMapper.md)
+ [Change data capture for DynamoDB Streams](Streams.md)

You can get started quickly by using Eclipse with the [Amazon Toolkit for Eclipse](http://www.amazonaws.cn/eclipse/). In addition to a full-featured IDE, you also get the Amazon SDK for Java with automatic updates, and preconfigured templates for building Amazon applications.

**To run the Java code examples (using Eclipse)**

1. Download and install the [Eclipse](http://www.eclipse.org) IDE.

1. Download and install the [Amazon Toolkit for Eclipse](http://www.amazonaws.cn/eclipse/).

1. Start Eclipse, and on the **Eclipse** menu, choose **File**, **New**, and then **Other**.

1. In **Select a wizard**, choose **Amazon**, choose **Amazon Java Project**, and then choose **Next**.

1. In **Create an Amazon Java**, do the following:

   1. In **Project name**, enter a name for your project.

   1. In **Select Account**, choose your credentials profile from the list.

      If this is your first time using the [Amazon Toolkit for Eclipse](http://www.amazonaws.cn/eclipse/), choose **Configure Amazon Accounts** to set up your Amazon credentials.

1. Choose **Finish** to create the project.

1. From the **Eclipse** menu, choose **File**, **New**, and then **Class**.

1. In **Java Class**, enter a name for your class in **Name** (use the same name as the code example that you want to run), and then choose **Finish** to create the class.

1. Copy the code example from the documentation page into the Eclipse editor.

1. To run the code, choose **Run** on the Eclipse menu.

The SDK for Java provides thread-safe clients for working with DynamoDB. As a best practice, your applications should create one client and reuse the client between threads.

For more information, see the [Amazon SDK for Java](http://www.amazonaws.cn/sdk-for-java).

**Note**  
The code examples in this guide are intended for use with the latest version of the Amazon SDK for Java.  
If you are using the Amazon Toolkit for Eclipse, you can configure automatic updates for the SDK for Java. To do this in Eclipse, go to **Preferences** and choose **Amazon Toolkit**, **Amazon SDK for Java**, **Download new SDKs automatically**.

## Java: Setting your Amazon credentials
<a name="CodeSamples.Java.Credentials"></a>

The SDK for Java requires that you provide Amazon credentials to your application at runtime. The code examples in this guide assume that you are using an Amazon credentials file, as described in [Set up your Amazon credentials](https://docs.amazonaws.cn/sdk-for-java/latest/developer-guide/set-up-creds.html) in the *Amazon SDK for Java Developer Guide*.

The following is an example of an Amazon credentials file named `~/.aws/credentials`, where the tilde character (`~`) represents your home directory.

```
[default]
aws_access_key_id = Amazon access key ID goes here
aws_secret_access_key = Secret key goes here
```

## Java: Setting the Amazon Region and endpoint
<a name="CodeSamples.Java.RegionAndEndpoint"></a>

By default, the code examples access DynamoDB in the US West (Oregon) Region. You can change the Region by modifying the `AmazonDynamoDB` properties.

The following code example instantiates a new `AmazonDynamoDB`.

```
import software.amazon.dynamodb.AmazonDynamoDBClientBuilder;
import com.amazonaws.regions.Regions;
...
// This client will default to US West (Oregon)
AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard()
.withRegion(Regions.US_WEST_2)
.build();
```

You can use the `withRegion` method to run your code against DynamoDB in any Region where it is available. For a complete list, see [Amazon regions and endpoints](https://docs.amazonaws.cn/general/latest/gr/rande.html#ddb_region) in the *Amazon Web Services General Reference*.

If you want to run the code examples using DynamoDB locally on your computer, set the endpoint as follows.

### Amazon SDK V1
<a name="CodeSamples.Java.RegionAndEndpoint.V1"></a>

```
AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().withEndpointConfiguration(
new AwsClientBuilder.EndpointConfiguration("http://localhost:8000", "us-west-2"))
.build();
```

### Amazon SDK V2
<a name="CodeSamples.Java.RegionAndEndpoint.V2"></a>

```
DynamoDbClient client = DynamoDbClient.builder()
    .endpointOverride(URI.create("http://localhost:8000"))
    // The region is meaningless for local DynamoDb but required for client builder validation
    .region(Region.US_EAST_1)
    .credentialsProvider(StaticCredentialsProvider.create(
    AwsBasicCredentials.create("dummy-key", "dummy-secret")))
    .build();
```