Model 1 architecture is one of the initial architecture styles used to develop Java-based web applications. A few important details are as follows:

• Java Server Pages (JSP) pages handle directly the requests from the browser.
• JSP pages make use of the model containing simple Java beans.
• In some applications of this architecture style, JSPs even perform queries to the database.
• JSPs also handle the flow logic—which page to show next.

The following diagram represents a typical Model 1 architecture:

There are a lot of disadvantages associated with this approach, leading to quick shelving and the evolution of other architectures. A few important disadvantages are listed as follows:

• Hardly any separation of concerns: JSPs are responsible for retrieving data, displaying data, deciding which pages to show next (flow), and sometimes, even business logic as well.
• Complex JSPs: Because JSPs handle a lot of logic, they are huge and difficult to maintain.