public Integer getIpv6AddressCount() {
        return this.ipv6AddressCount;
    }
<p>
The number of IPv6 addresses to assign to a network interface. Amazon EC2 automatically selects the IPv6
addresses from the subnet range.
</p>
<p>
You can't specify a count of IPv6 addresses using this parameter if you've specified one of the following:
specific IPv6 addresses, specific IPv6 prefixes, or a count of IPv6 prefixes.
</p>
<p>
If your subnet has the <code>AssignIpv6AddressOnCreation</code> attribute set, you can override that setting by
specifying 0 as the IPv6 address count.
</p>

@return The number of IPv6 addresses to assign to a network interface. Amazon EC2 automatically selects the IPv6
        addresses from the subnet range.</p>
        <p>
        You can't specify a count of IPv6 addresses using this parameter if you've specified one of the
        following: specific IPv6 addresses, specific IPv6 prefixes, or a count of IPv6 prefixes.
        </p>
        <p>
        If your subnet has the <code>AssignIpv6AddressOnCreation</code> attribute set, you can override that
        setting by specifying 0 as the IPv6 address count.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/CreateNetworkInterfaceRequest.java