public java.util.List<String> getCredentialSpecs() {
        if (credentialSpecs == null) {
            credentialSpecs = new com.amazonaws.internal.SdkInternalList<String>();
        }
        return credentialSpecs;
    }
<p>
A list of ARNs in SSM or Amazon S3 to a credential spec (<code>CredSpec</code>) file that configures the
container for Active Directory authentication. We recommend that you use this parameter instead of the
<code>dockerSecurityOptions</code>. The maximum number of ARNs is 1.
</p>
<p>
There are two formats for each ARN.
</p>
<dl>
<dt>credentialspecdomainless:MyARN</dt>
<dd>
<p>
You use <code>credentialspecdomainless:MyARN</code> to provide a <code>CredSpec</code> with an additional section
for a secret in Secrets Manager. You provide the login credentials to the domain in the secret.
</p>
<p>
Each task that runs on any container instance can join different domains.
</p>
<p>
You can use this format without joining the container instance to a domain.
</p>
</dd>
<dt>credentialspec:MyARN</dt>
<dd>
<p>
You use <code>credentialspec:MyARN</code> to provide a <code>CredSpec</code> for a single domain.
</p>
<p>
You must join the container instance to the domain before you start any tasks that use this task definition.
</p>
</dd>
</dl>
<p>
In both formats, replace <code>MyARN</code> with the ARN in SSM or Amazon S3.
</p>
<p>
If you provide a <code>credentialspecdomainless:MyARN</code>, the <code>credspec</code> must provide a ARN in
Secrets Manager for a secret containing the username, password, and the domain to connect to. For better
security, the instance isn't joined to the domain for domainless authentication. Other applications on the
instance can't use the domainless credentials. You can use this parameter to run tasks on the same instance, even
it the tasks need to join different domains. For more information, see <a
href="https://docs.aws.amazon.com/AmazonECS/latest/developerguide/windows-gmsa.html">Using gMSAs for Windows
Containers</a> and <a href="https://docs.aws.amazon.com/AmazonECS/latest/developerguide/linux-gmsa.html">Using
gMSAs for Linux Containers</a>.
</p>

@return A list of ARNs in SSM or Amazon S3 to a credential spec (<code>CredSpec</code>) file that configures the
        container for Active Directory authentication. We recommend that you use this parameter instead of the
        <code>dockerSecurityOptions</code>. The maximum number of ARNs is 1.</p>
        <p>
        There are two formats for each ARN.
        </p>
        <dl>
        <dt>credentialspecdomainless:MyARN</dt>
        <dd>
        <p>
        You use <code>credentialspecdomainless:MyARN</code> to provide a <code>CredSpec</code> with an additional
        section for a secret in Secrets Manager. You provide the login credentials to the domain in the secret.
        </p>
        <p>
        Each task that runs on any container instance can join different domains.
        </p>
        <p>
        You can use this format without joining the container instance to a domain.
        </p>
        </dd>
        <dt>credentialspec:MyARN</dt>
        <dd>
        <p>
        You use <code>credentialspec:MyARN</code> to provide a <code>CredSpec</code> for a single domain.
        </p>
        <p>
        You must join the container instance to the domain before you start any tasks that use this task
        definition.
        </p>
        </dd>
        </dl>
        <p>
        In both formats, replace <code>MyARN</code> with the ARN in SSM or Amazon S3.
        </p>
        <p>
        If you provide a <code>credentialspecdomainless:MyARN</code>, the <code>credspec</code> must provide a
        ARN in Secrets Manager for a secret containing the username, password, and the domain to connect to. For
        better security, the instance isn't joined to the domain for domainless authentication. Other
        applications on the instance can't use the domainless credentials. You can use this parameter to run
        tasks on the same instance, even it the tasks need to join different domains. For more information, see
        <a href="https://docs.aws.amazon.com/AmazonECS/latest/developerguide/windows-gmsa.html">Using gMSAs for
        Windows Containers</a> and <a
        href="https://docs.aws.amazon.com/AmazonECS/latest/developerguide/linux-gmsa.html">Using gMSAs for Linux
        Containers</a>.
aws-java-sdk-ecs/src/main/java/com/amazonaws/services/ecs/model/ContainerDefinition.java