Struts 2 is a web framework that is designed to help developers build complex, high-performance web applications. To achieve this, Struts 2 provides a number of key elements that work together to provide a powerful and flexible development platform. Here are the main Struts 2 elements:

1. Actions: Actions are the main processing units in a Struts 2 application. They are responsible for processing user requests, performing business logic, and generating output. Actions are implemented as Java classes that implement the Action interface.

2. Results: Results are the output produced by an action. They can be in the form of JSP pages, FreeMarker templates, PDF files, or any other type of output. Results are typically defined in the struts.xml configuration file and are associated with a specific action.

3. Interceptors: Interceptors are components that are used to preprocess and postprocess requests and responses. They are responsible for tasks such as authentication, validation, logging, and exception handling. Interceptors are defined in the struts.xml configuration file and are associated with a specific action.

4. Value Stack: The Value Stack is a data structure that is used to pass data between actions and views. It is essentially a stack of maps that contain the data used by an action or a view. The Value Stack is a core feature of Struts 2 and is used extensively throughout the framework.

5. Tags: Tags are custom JSP tags that are used to generate Struts 2-specific HTML and other markup. They are used to create forms, links, tables, and other UI components. Tags are defined in the struts-tags.tld file and can be used in any JSP page that includes the Struts 2 tag library.

6. Configuration files: Configuration files are used to define the behavior of a Struts 2 application. The main configuration file is struts.xml, which defines the action mappings, interceptors, and results. Other configuration files include struts.properties, web.xml, and the validation and localization files.

Overall, these Struts 2 elements work together to provide a powerful and flexible development platform for building complex, high-performance web applications. By leveraging these elements and the other features of Struts 2, developers can create robust and scalable web applications that meet the needs of their users.