# Connecting to Amazon Neptune databases using IAM authentication with Java and SPARQL
<a name="iam-auth-connecting-sparql-java"></a>

This section shows how to connect to Neptune using either RDF4J or Apache Jena with Signature Version 4 authentication.

**Prerequisites**
+ Java 8 or higher.
+ Apache Maven 3.3 or higher.

  For information about installing these prerequisites on an EC2 instance running Amazon Linux, see [Prerequisites for connecting Amazon Neptune databases using IAM authentication](iam-auth-connect-prerq.md).
+ IAM credentials to sign the requests. For more information, see [Using the Default Credential Provider Chain](https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/credentials.html#credentials-default) in the *AWS SDK for Java Developer Guide*.
**Note**  
If you are using temporary credentials, they expire after a specified interval, *including the session token*.  
You must update your session token when you request new credentials. For more information, see [Using Temporary Security Credentials to Request Access to AWS Resources](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_temp_use-resources.html) in the *IAM User Guide*.
+ Set the `SERVICE_REGION` variable to one of the following, indicating the Region of your Neptune DB instance:
  + US East (N. Virginia):   `us-east-1`
  + US East (Ohio):   `us-east-2`
  + US West (N. California):   `us-west-1`
  + US West (Oregon):   `us-west-2`
  + Canada (Central):   `ca-central-1`
  + Canada West (Calgary):   `ca-west-1`
  + South America (São Paulo):   `sa-east-1`
  + Europe (Stockholm):   `eu-north-1`
  + Europe (Spain):   `eu-south-2`
  + Europe (Ireland):   `eu-west-1`
  + Europe (London):   `eu-west-2`
  + Europe (Paris):   `eu-west-3`
  + Europe (Frankfurt):   `eu-central-1`
  + Middle East (Bahrain):   `me-south-1`
  + Middle East (UAE):   `me-central-1`
  + Israel (Tel Aviv):   `il-central-1`
  + Africa (Cape Town):   `af-south-1`
  + Asia Pacific (Hong Kong):   `ap-east-1`
  + Asia Pacific (Tokyo):   `ap-northeast-1`
  + Asia Pacific (Seoul):   `ap-northeast-2`
  + Asia Pacific (Osaka):   `ap-northeast-3`
  + Asia Pacific (Singapore):   `ap-southeast-1`
  + Asia Pacific (Sydney):   `ap-southeast-2`
  + Asia Pacific (Jakarta):   `ap-southeast-3`
  + Asia Pacific (Melbourne):   `ap-southeast-4`
  + Asia Pacific (Malaysia):   `ap-southeast-5`
  + Asia Pacific (Mumbai):   `ap-south-1`
  + Asia Pacific (Hyderabad):   `ap-south-2`
  + China (Beijing):   `cn-north-1`
  + China (Ningxia):   `cn-northwest-1`
  + AWS GovCloud (US-West):   `us-gov-west-1`
  + AWS GovCloud (US-East):   `us-gov-east-1`

**To connect to Neptune using either RDF4J or Apache Jena with Signature Version 4 signing**

1. Clone the sample repository from GitHub.

   ```
   git clone https://github.com/aws/amazon-neptune-sparql-java-sigv4.git
   ```

1. Change into the cloned directory.

   ```
   cd amazon-neptune-sparql-java-sigv4
   ```

1. Get the latest version of the project by checking out the branch with the latest tag.

   ```
   git checkout $(git describe --tags `git rev-list --tags --max-count=1`)
   ```

1. Enter one of the following commands to compile and run the example code.

   Replace *your-neptune-endpoint* with the hostname or IP address of your Neptune DB instance. The default port is 8182.
**Note**  
For information about finding the hostname of your Neptune DB instance, see the [Connecting to Amazon Neptune Endpoints](feature-overview-endpoints.md) section.

**Eclipse RDF4J**  
Enter the following to run the RDF4J example.

   ```
   mvn compile exec:java \
       -Dexec.mainClass="com.amazonaws.neptune.client.rdf4j.NeptuneRdf4JSigV4Example" \
       -Dexec.args="https://your-neptune-endpoint:portsparql region-name"
   ```

**Apache Jena**  
Enter the following to run the Apache Jena example.

   ```
   mvn compile exec:java \
       -Dexec.mainClass="com.amazonaws.neptune.client.jena.NeptuneJenaSigV4Example" \
       -Dexec.args="https://your-neptune-endpoint:port"
   ```

1. To view the source code for the example, see the examples in the `src/main/java/com/amazonaws/neptune/client/` directory.

To use the SigV4 signing driver in your own Java application, add the `amazon-neptune-sigv4-signer` Maven package to the `<dependencies>` section of your `pom.xml`. We recommend that you use the examples as a starting point.