public ProviderUserIdentifierType getDestinationUser() {
        return this.destinationUser;
    }
<p>
The existing user in the user pool that you want to assign to the external IdP user account. This user can be a
local (Username + Password) Amazon Cognito user pools user or a federated user (for example, a SAML or Facebook
user). If the user doesn't exist, Amazon Cognito generates an exception. Amazon Cognito returns this user when
the new user (with the linked IdP attribute) signs in.
</p>
<p>
For a native username + password user, the <code>ProviderAttributeValue</code> for the
<code>DestinationUser</code> should be the username in the user pool. For a federated user, it should be the
provider-specific <code>user_id</code>.
</p>
<p>
The <code>ProviderAttributeName</code> of the <code>DestinationUser</code> is ignored.
</p>
<p>
The <code>ProviderName</code> should be set to <code>Cognito</code> for users in Cognito user pools.
</p>
<important>
<p>
All attributes in the DestinationUser profile must be mutable. If you have assigned the user any immutable custom
attributes, the operation won't succeed.
</p>
</important>

@return The existing user in the user pool that you want to assign to the external IdP user account. This user
        can be a local (Username + Password) Amazon Cognito user pools user or a federated user (for example, a
        SAML or Facebook user). If the user doesn't exist, Amazon Cognito generates an exception. Amazon Cognito
        returns this user when the new user (with the linked IdP attribute) signs in.</p>
        <p>
        For a native username + password user, the <code>ProviderAttributeValue</code> for the
        <code>DestinationUser</code> should be the username in the user pool. For a federated user, it should be
        the provider-specific <code>user_id</code>.
        </p>
        <p>
        The <code>ProviderAttributeName</code> of the <code>DestinationUser</code> is ignored.
        </p>
        <p>
        The <code>ProviderName</code> should be set to <code>Cognito</code> for users in Cognito user pools.
        </p>
        <important>
        <p>
        All attributes in the DestinationUser profile must be mutable. If you have assigned the user any
        immutable custom attributes, the operation won't succeed.
        </p>
aws-java-sdk-cognitoidp/src/main/java/com/amazonaws/services/cognitoidp/model/AdminLinkProviderForUserRequest.java