JSP Compiler and ClassCastException

Answer 1

Have been using JDK1.2.2 from sun since day one and I've been seeing
          ClassCastException since day 1 too.
          Don't think it had anything to do with the compiler.
          "Jun Ying" <[email protected]> wrote in message
          news:[email protected]...
          > I noticed something that might be causing the ClassCastException and has
          not
          > been mentioned: the compiler that is used for jspc. I remember seeing a
          few
          > people mentioning extra classes in the workDir (ie, the bean class that is
          > being used). This is caused by using a smart compiler such as jikes or
          sj.
          > While those compilers will get you more speed for newly modified jsp's,
          they
          > resolve dependencies and recompile all the referenced classes. The result
          > is that the bean class gets recompiled and put into workDir. So no matter
          > where you put the workDir, you end up getting a new copy of the bean class
          > file, which is reloaded by the classloader that loads the newly compiled
          > JSP. That copy of the class file is considered "different" from the one
          > from the normal system classpath or the weblogic.class.path. Thus the
          > ClassCastException. So if you see java classes other than the jsp's in
          the
          > workDir, make sure you are using javac from the sun jdk. So to answer
          > Anish's question, WebLogic is not sticking a copy of the bean class.
          > Rather, it's the java compiler that you are using.
          >
          > Jun Ying
          > Meritsoft, Inc
          >
          >
          > "Michael Boudreau" <[email protected]> wrote in message
          > news:[email protected]...
          > > Hello,
          > >
          > > Well we ran into the same problem here at my company, and we have been
          > > pulling our hair out. I was reading through the jsp 1.1 spec, and
          > > thought I might try using the <jsp:useBean ...> tag instead of the <%@
          > > page import ...> tag. After careful inspection of the resulting .java
          > > file, I found that the <jsp:useBean ...> tag does not put insert any
          > > import statements, but simply declares the bean with the fully
          > > qualified package name. I am sure that this is not new news to anyone;
          > > however, the class cast exception went away (knock on wood, cross
          > > fingers, whatever).
          > >
          > > Basically, my statement looked like this:
          > > <jsp:useBean id="beanname" type="com.company.Class" scope="session" />
          > >
          > > My question is: is there something that I am missing or have not
          > > thought of? Because so far, this "seems" to be working, but I have
          > > been reading posts that say this does not work.
          > >
          > > Oh, one last quick note to BEA. While I was looking at the
          > > generated .java file from the jsp file, I found that weblogic's jspc is
          > > still generating getValue and setValue methods for HttpSession....
          > > which has been deprecated as of the servlet 2.2 spec.
          > >
          > > Michael
          > >
          > >
          > >
          > >
          > > Anish Parvataneni wrote:
          > >
          > > > Hi,
          > > >
          > > > I have a JSP which uses two different classes. Whenever, I change the
          > > > JSP and save it to recompile, there is a ClassCastException. ( I store
          > > > them in the session and load them) . Thats common ! The solution to
          this
          > > > as per documentation is to get rid of the classes in the workingDir of
          > > > JSP. However, I can find ONLY ONE of the classes in the workingDir. I
          > > > delete that class and the JSP works. I change the JSP , problem
          recurrs.
          > > >
          > > > 1. Why does weblogic stick a copy of the class in the workingDir,
          > > > everytime the JSP compiles, although it is available in the weblogic
          > > > classpath ?
          > > > 2. Why is it happening to only one of the classes I use in the JSP ?
          > > > 3. How can I make sure that this class is not available in the
          > > > workingDir, other than deleting it EVERYTIME.
          > > >
          > > > Thanks
          > > > Anish
          > >
          >
          >