The way any web application works involves the Back-end part of the web program, which runs on the server, and the Front-end part of the web application, which runs on the user’s device.

The main calculations in any case occur on the server. After receiving a request from the browser of the client device, the server part of the web application, using information from the database, generates the result of calculations. This result is sent to the end device, processed by the client side of the web application, and rendered in the web browser in the form of a user interface.

Creating web applications in Java is essentially creating server-side programs, so-called servlets. These Java applications extend the capabilities of the server and allow to perform a variety of functions:

after a user’s request, a so-called Java virtual machine runs on the server;
it executes a servlet, i.e. activates a specific web application written in Java;
When the servlet finishes, the web server sends the result of the computation to the end device in the form of a dynamic web page.

Because Java programs are executed in a Java virtual machine environment that can be deployed on any computer architecture, this technology is not tied to a single platform. Web applications written in Java can run on any devices and servers regardless of the operating system and hardware type.

At the same time, using frameworks like Spring simplifies and automates servlet configuration with a framework model. Automation and acceleration of large web applications is made possible because the Spring framework involves the use of a so-called central servlet, which redirects user calls to one or the other web services, web services, and web components. It is the support of the infrastructure at the application level that facilitates quick construction and easy execution of the corporate business logic of the program without changing configurations and additional settings.