public String getUsername() {
        return this.username;
    }
<p>
The value that you want to set as the username sign-in attribute. The following conditions apply to the username
parameter.
</p>
<ul>
<li>
<p>
The username can't be a duplicate of another username in the same user pool.
</p>
</li>
<li>
<p>
You can't change the value of a username after you create it.
</p>
</li>
<li>
<p>
You can only provide a value if usernames are a valid sign-in attribute for your user pool. If your user pool
only supports phone numbers or email addresses as sign-in attributes, Amazon Cognito automatically generates a
username value. For more information, see <a href=
"https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html#user-pool-settings-aliases"
>Customizing sign-in attributes</a>.
</p>
</li>
</ul>

@return The value that you want to set as the username sign-in attribute. The following conditions apply to the
        username parameter.</p>
        <ul>
        <li>
        <p>
        The username can't be a duplicate of another username in the same user pool.
        </p>
        </li>
        <li>
        <p>
        You can't change the value of a username after you create it.
        </p>
        </li>
        <li>
        <p>
        You can only provide a value if usernames are a valid sign-in attribute for your user pool. If your user
        pool only supports phone numbers or email addresses as sign-in attributes, Amazon Cognito automatically
        generates a username value. For more information, see <a href=
        "https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html#user-pool-settings-aliases"
        >Customizing sign-in attributes</a>.
        </p>
        </li>
aws-java-sdk-cognitoidp/src/main/java/com/amazonaws/services/cognitoidp/model/AdminCreateUserRequest.java