javax.servlet.ServletException: bean [name] not found within scope

java, jsp, usebean

Solution

You need the `class` attribute instead of the `type` attribute.

The following:

<jsp:useBean id="bean" type="com.example.Bean" scope="request" />

does basically the following behind the scenes:

Bean bean = (Bean) pageContext.getAttribute("bean", PageContext.REQUEST_SCOPE);

if (bean == null) {
    throw new ServletException("bean not found within scope");
}

// Use bean ...

While the following:

<jsp:useBean id="bean" class="com.example.Bean" scope="request" />

does basically the following behind the scenes:

Bean bean = (Bean) pageContext.getAttribute("bean", PageContext.REQUEST_SCOPE);

if (bean == null) {
    bean = new Bean();
    pageContext.setAttribute("bean", bean, PageContext.REQUEST_SCOPE);
}

// Use bean ...

If it has worked before and it didn't work "in a sudden", then it means that something which is responsible for putting the bean in the scope has stopped working. For example a servlet which does the following in the `doGet()`:

request.setAttribute("bean", new Bean());
request.getRequestDispatcher("page.jsp").forward(request, response);

Maybe you've invoked the JSP page directly by URL instead of invoking the Servlet by URL. If you'd like to disable direct access to JSP pages, then put them in `/WEB-INF` and forward to it instead.

Problem

Original source