The following article explains What is a JSP Action.

Basically, a JSP action is a special type of JSP tag that we use to perform a specific action, such as including another file, setting a variable, or invoking a method. JSP actions are used to enhance the functionality of a JSP page by encapsulating commonly used functionality into reusable components.

Further, JSP actions are typically denoted by an <jsp: prefix, followed by a specific action name and one or more attributes. The following code shows some examples of common JSP actions.

jsp:include. In order to include the contents of another file or resource into the current JSP page, we use this action. For example.

<jsp:include page="header.jsp" />

jsp:useBean. We use it to create or retrieve a JavaBean and store it as a variable in the JSP page. For example.

<jsp:useBean id="user" class="com.example.User" scope="session" />

jsp:setProperty. In order to set the properties of a JavaBean using the values of request parameters or other variables, we use this action. For example.

<jsp:setProperty name="user" property="name" value="${param.username}" />

jsp:getProperty. In order to retrieve the value of a property from a JavaBean and display it on the JSP page, we use it. For example.

<p>Welcome, ${jsp:getProperty name="user" property="name"}!</p>

jsp:forward. Basically, we can forward the current request using jsp:forward. As a result, another JSP or servlet gets executed to which the request is forwarded. For example.

<jsp:forward page="dashboard.jsp" />

To summarize, JSP actions add functionality to a JSP page without requiring additional Java code and can help to improve code modularity and maintainability.

Further Reading

Spring Framework Practice Problems and Their Solutions

Java Practice Exercise