# Memory Classes

[**Memory Classes**](https://jframework.gitbook.io/developers/terms-definitions-abbreviations-and-regulations/definitions/memory-class) are classes, most of which provide utility methods to work with Entity Classes. Some provide utility methods to handle business processes. Memory classes are based on memory.

[Memory Classes](https://jframework.gitbook.io/developers/terms-definitions-abbreviations-and-regulations/definitions/memory-class) help you to handle tasks like sending emails, generating tokens, managing sessions, etc. These classes don't manipulate the database, but they can be used to store data in the memory. For example, you can use the [CSessionManager](https://jframework.gitbook.io/developers/essentials/memory-classes/session-manager) to store the user instance in the memory, and you can use the [CEmail](https://jframework.gitbook.io/developers/essentials/memory-classes/mail-service) to send emails. For more information, please refer to the following sections:

{% content-ref url="memory-classes/error-manager" %}
[error-manager](https://jframework.gitbook.io/developers/essentials/memory-classes/error-manager)
{% endcontent-ref %}

{% content-ref url="memory-classes/mail-service" %}
[mail-service](https://jframework.gitbook.io/developers/essentials/memory-classes/mail-service)
{% endcontent-ref %}

{% content-ref url="memory-classes/session-manager" %}
[session-manager](https://jframework.gitbook.io/developers/essentials/memory-classes/session-manager)
{% endcontent-ref %}

{% content-ref url="memory-classes/token-service-class" %}
[token-service-class](https://jframework.gitbook.io/developers/essentials/memory-classes/token-service-class)
{% endcontent-ref %}

{% content-ref url="memory-classes/version" %}
[version](https://jframework.gitbook.io/developers/essentials/memory-classes/version)
{% endcontent-ref %}