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jkelsey
Posts: 12
Posted 23:48 Apr 20, 2011 |

Dr. Sun,


I realize that I'm bringing up this problem 15 minutes before the deadline. However, after our class, I had to finish a reading assignment for my evening class, which itself started at 6:10 (CS 337). I got out at 9:00 pm and then rushed home to finish the lab.


I've completed most of the lab, however, I'm having a problem getting pass these exceptions when I attempt to run my Test.jsp file:

org.apache.jasper.JasperException: /Test.jsp(7,0) The value for the useBean class attribute cs320.lab.TestBean is invalid.
org.apache.jasper.JasperException: java.lang.ClassNotFoundException: org.apache.jsp.Test_jsp

I get these two randomly alternating exceptions, regardless if I change my code or not. All of my classes are in cs320.lab package. I've Googled this problem and asked on #java Freenode and run through many attempted fixes but I can't get pass this same exception. I've even done manual copies of the class files to WEB-INF/classes/cs320/lab. Here is the tag I am using:

<jsp:useBean class="cs320.lab.TestBean" id="tb" scope="application" />

Well anyways, it's probably too late to fix this before midnight, so I'll just upload what I've got.

Last edited by jkelsey at 23:50 Apr 20, 2011.
abess
Posts: 26
Posted 23:50 Apr 20, 2011 |

Coincidentally, I am getting the exact same errors...

frodrig3
Posts: 2
Posted 00:52 Apr 21, 2011 |

same here, I stopped development at this point and just turned in what I had.

I'd hate to see the time and effort put in amount to nothing, hopefully there's partial credit?

abess
Posts: 26
Posted 01:07 Apr 21, 2011 |

I did the same, some partial credit would be nice, but considering I could not even get it working on my local host, I doubt it would actually work normally on a working server...

cysun
Posts: 2935
Posted 08:07 Apr 21, 2011 |

Remember a JSP is converted to a servlet by the server. If there's something wrong with the bean, the servlet (org.apache.jsp.Test_jsp.java in this case) cannot be generated, and you'll get a ClassNotFound error.

The proper way to debug is to first try some code that is known to work, e.g. BGBean & BGColor, then try replacing TestBean with a simple bean. If both work, the problem is likely with your TestBean; if neither works, it's likely an Eclipse problem.

Eclipse is known to have weird problems from time to time, though rarely for simple projects like this (I do have a feeling that the latest Eclipse release is not very stable). If you think it's an Eclipse problem, follow the instructions in this thread to clean the Eclipse work directory.