# Prerequisites for connecting Amazon Neptune databases using IAM authentication
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The following are instructions for installing Apache Maven and Java 8 on an Amazon EC2 instance. These are required for the Amazon Neptune Signature Version 4 authentication samples.

**To Install Apache Maven and Java 8 on your EC2 instance**

1. Connect to your Amazon EC2 instance with an SSH client.

1. Install Apache Maven on your EC2 instance. If using Amazon Linux 2023 (preferred), use:

   ```
   sudo dnf update -y
   sudo dnf install maven -y
   ```

   If using Amazon Linux 2, download the latest binary from [ https://maven.apache.org/download.cgi: ](https://maven.apache.org/download.cgi:)

   ```
   sudo yum remove maven -y
   wget https://dlcdn.apache.org/maven/maven-3/ <version>/binaries/apache-maven-<version>-bin.tar.gz
   sudo tar -xzf apache-maven-<version>-bin.tar.gz -C /opt/
   sudo ln -sf /opt/apache-maven-<version> /opt/maven
   echo 'export MAVEN_HOME=/opt/maven' >> ~/.bashrc
   echo 'export PATH=$MAVEN_HOME/bin:$PATH' >> ~/.bashrc
   source ~/.bashrc
   ```

1. The Gremlin libraries require Java 8. Enter the following to install Java 8 on your EC2 instance.

   ```
   sudo yum install java-1.8.0-devel
   ```

1. Enter the following to set Java 8 as the default runtime on your EC2 instance.

   ```
   sudo /usr/sbin/alternatives --config java
   ```

   When prompted, enter the number for Java 8.

1. Enter the following to set Java 8 as the default compiler on your EC2 instance.

   ```
   sudo /usr/sbin/alternatives --config javac
   ```

   When prompted, enter the number for Java 8.