public String getClientRequestToken() {
        return this.clientRequestToken;
    }
<p>
A unique case-sensitive string used to ensure the request to create the session is idempotent (executes only
once). If another <code>StartSessionRequest</code> is received, the same response is returned and another session
is not created. If a parameter has changed, an error is returned.
</p>
<important>
<p>
This token is listed as not required because Amazon Web Services SDKs (for example the Amazon Web Services SDK
for Java) auto-generate the token for users. If you are not using the Amazon Web Services SDK or the Amazon Web
Services CLI, you must provide this token or the action will fail.
</p>
</important>

@return A unique case-sensitive string used to ensure the request to create the session is idempotent (executes
        only once). If another <code>StartSessionRequest</code> is received, the same response is returned and
        another session is not created. If a parameter has changed, an error is returned.</p> <important>
        <p>
        This token is listed as not required because Amazon Web Services SDKs (for example the Amazon Web
        Services SDK for Java) auto-generate the token for users. If you are not using the Amazon Web Services
        SDK or the Amazon Web Services CLI, you must provide this token or the action will fail.
        </p>
aws-java-sdk-athena/src/main/java/com/amazonaws/services/athena/model/StartSessionRequest.java