tLogin(java.security.Principal, java.util.Set)</code></a> method.

 <p>
 Implementations are expected and encouraged to delegate the actual credential validation and/or retrieval of the
 caller name with optional groups to an <a href="../../../identitystore/IdentityStore.html" title="interface in jakarta.security.enterprise.identitystore"><code>IdentityStore</code></a>. This is however <b>not</b> required and implementations
 can either do the validation checks for authentication completely autonomously, or