Possible error on HFS and errata

[Zhing Lam]

Hello, can someone confirm me the follow:
In the errata published at OReilly, say that the page 432, Q17, the option C (If the . operator is used to access a bean property but the property doesn't exit, the a runtime exception is thrown) "is invalid and should not be checked." but I think the option C is OK, I test it at tomcat, and that was OK (throw exception), the same problem I found at page 447, that say "EL expression by itself will not cause an exception if the property doesn't exist". That can justify at JSP spec, pag 105 (last line of JSP2.3.4).

[sundar katluri]

As far as i know you miss understood the spec
what it says is (the last line what you mentioned) if you use $expr-a.identifier-b
expr-a evaluates to other than map or bean then gives the error

I use Tomcat 5.5.4 if i call ${person.name} in a jsp not giving any error(without setting "person" attribute in any of the four scope )
but
if you set attribute "person" with array then container gives the error
because syntax $expr-a.identifier-b takes only bean or map
here is example....

 <%
String movies = {"spiderman","meet the fockers"};
  request.setAttribute("person",movies);
%>
Dear ${person.name} 

gives following error in tomcat 5.5.4

 type Exception report
 
message 
 
description The server encountered an internal error () that prevented it from fulfilling this request.
 
exception 
 
org.apache.jasper.JasperException: Unable to compile class for JSP
 
An error occurred at line: 13 in the jsp file: /test.jsp
Generated servlet error:
Type mismatch: cannot convert from String[] to String
 

  

[sundar katluri]

sorry that was compliation error i mentioned previously
here is the actual erro from tomcat 5.5.4

  type Exception report
 
message 
 
description The server encountered an internal error () that prevented it from fulfilling this request.
 
exception 
 
javax.servlet.ServletException: The "." operator was supplied with an index value of type "java.lang.String" to be applied to a List or array, but that value cannot be converted to an integer.
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:845)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:778)
org.apache.jsp.test_jsp._jspService(org.apache.jsp.test_jsp:70)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
 

root cause 
 
javax.servlet.jsp.el.ELException: The "." operator was supplied with an index value of type "java.lang.String" to be applied to a List or array, but that value cannot be converted to an integer.
org.apache.commons.el.Logger.logError(Logger.java:481)
org.apache.commons.el.Logger.logError(Logger.java:498)
 

[Zhing Lam]

Exactly man, in ${person.aNotExistProperty}, if "person" not exist (null), it isn't the problem, the case I refer is when "person" (important, "person" is a bean, not a map) exists in some scope (not null), and you access a property that not exist, is exception.

[sundar katluri]

you are right. Now i realized ,if the bean exist and the property does not exist in the bean then it throws exception .


Thanks

[Nitish Bahadur]

Zhing,
Unless proved other wise, I think you are right. As mentioned in your post, JSP 2.0 Specification, Pg 105 Pg 2.3.4 clearly mentions how EL expressions are evaluated.

Sundar,
I think you have a syntax error(String [] vs String) in your JSP. Additionally, the treatment of List and Array is a little different from Javabeans.

~Cheers