public String getActiveDirectoryId() {
        return this.activeDirectoryId;
    }
<p>
The ID for an existing Amazon Web Services Managed Microsoft Active Directory instance that the file system is
joined to.
</p>

@return The ID for an existing Amazon Web Services Managed Microsoft Active Directory instance that the file
        system is joined to.
aws-java-sdk-fsx/src/main/java/com/amazonaws/services/fsx/model/WindowsFileSystemConfiguration.java