NumberFormatException ArrayList size Javabean method in JSP with JSTL

Question

Im a little new to JSTL and Javabeans so I'm having a lot of trouble figuring this one out.

I have an index.jsp, a class called CustomerScheme which extends an ArrayList, and a test.jsp which im using for output.

index.jsp contains the following code, and has a link to test.jsp:

<jsp:useBean id="scheme" scope="session" class="customer.beans.CustomerScheme">

    <%
        // Open a stream to the init file
        InputStream stream =
                application.getResourceAsStream("/fm.txt");

        // Get a reference to the scheme bean
        CustomerScheme custScheme =
                (CustomerScheme) pageContext.findAttribute("scheme");

        // Load colors from stream
        try {
            custScheme.load(stream);
        } catch (IOException iox) {
            throw new JspException(iox);
        }
    %>

</jsp:useBean>

test.jsp contains:

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
${scheme.size}

CustomerScheme extends ArrayList, and has the method:

public int getSize() {
    return this.size();
}

CustomerScheme has more code. I'll post it if you need.

My problem is this: Whenever I run the program, I start at index.jsp, click the link to go to test.jsp, and then get the following:

Answer 1

The javax.el.ListELResolver handles base objects of type java.util.List. It accepts any object as a property and coerces that object into an integer index into the list.

So you need to call the getSize() method - ${scheme.getSize()} or use <jsp:getProperty/>

Alternatively, you can create a List<T> in customer.beans.CustomerScheme instead of extending ArrayList<T>.

public class CustomerScheme{
  private List<Customer> list=new ArrayList<Customer>();
  public int getSize(){
         return list.size();
  }
  ..
}