Re: Exception in Hessian Serialization

Hi Toby,
just looked into your past posting on the same problem and you link to an entry
in the java forum.http://forum.java.sun.com/thread.jspa?tstart=135&forumID=62&threadID=520000&trange=15

Knowing the Hessian implementation a little bit (and having changed
the code every now and then) I have doubts that transfering a FILE
object as property works at all.

Hessian has quit a number of built in serializers and deserializers
but none for FILE. As the entry in the java forum states (and
something I also observed). Hessian calls the constructor with
shortest argument least (preferable none). Since FILE only has a
constructor with one argument, Hessian calls it with the parameter
NULL. Since the FILE constructor checks on that and throws a
NullPointerException, constructing a FILE object that way fails (you
see the NullPointerException somewhere in your stacktrace). The
InvocationTargetException is thrown because calling an constructor
(initializer or <init>) failed when using reflection (that what
hessian does).

I can't believe it ever worked is the bottom line. A FILE object is a
handle to a physical file location on disk. Such a FILE handle is
meaning less when transported via a webservice.

What you want in the end is to transport a binary blob using
Webservices. I implemented such a thing and its pretty simple.
Create a class, call it Attachment. Allow it to be constructed with a
empty constructor (which does nothing and is used by hessian) and from
a FILE object or a URL or whatever.

When Hessian tries to transport it, it will call the methode
"writeReplace". Use it read the file
content into a byte array and set the file handle to NULL.

On the target platform (service or client does not matter), Hessian
calls the empty constructor, sets the byte array which is a private
property of your attachment instance and calls a method with
the name "readResolve". There you can create a temp file, write the
byte array into it, set the FILE handle and there you go.

BTW: read and writing file content that you don't know becomes easier
if you use JAF the
Java Activation Framework because it handles mime-types and all that.
So a file could
be easier accessed using the dataHandler from JAF and its easier to
write it if you
use JAF.

and questions, let me know

christian campo

On Tue, 14 Dec 2004 02:45:04 -0600, ejf <sun_king@xxx.net> wrote:
>
> you say that one the file transfers worked. was that transfer with Hessian?
> do you have example code??
> i'd love to work on an example...
>
> e.j. fuhr
>
>
>
>
> Toby Hede wrote:
>
> > I guess there is not much interest in the hessian interest list.
> > Is there another forum that addresses hessian issues?
> >
> > I am still experiencing my strange file transfer problem with with
> > Hessian.
> >
> > I am trying to send a serialized file through Hessian. Where
> > previously one of my file transfers worked and another failed, despite
> > using the same code, now they both fail.
> >
> > Any help would be appreciated.
> >
> > Windows XP SP2, JDK1.4.2_05, latest version Hessian
> >
> > Stack Trace:
> > java.lang.reflect.InvocationTargetException
> > at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
> > Method)
> > at
> > sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
> >
> > at
> > sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
> >
> > at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
> > at
> > com.caucho.hessian.io.JavaDeserializer.instantiate(JavaDeserializer.java:168)
> >
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:103)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:995)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:134)
> >
> > at
> > com.caucho.hessian.server.HessianServlet.service(HessianServlet.java:293)
> > at
> > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
> >
> > at
> > org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
> >
> > at
> > org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
> >
> > at
> > org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
> > at
> > org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
> > at
> > org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
> >
> > at
> > org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
> >
> > at
> > org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
> >
> > at
> > org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
> >
> > at java.lang.Thread.run(Thread.java:534)
> > Caused by: java.lang.NullPointerException
> > at sun.awt.shell.Win32ShellFolder2.<init>(Win32ShellFolder2.java:189)
> > ... 62 more
> > StandardWrapperValve[EcommerceService]: Servlet.service() for servlet
> > EcommerceService threw exception
> > java.io.IOException: java.lang.reflect.InvocationTargetException
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:112)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:995)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.SerializerFactory.readMap(SerializerFactory.java:222)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1120)
> > at
> > com.caucho.hessian.io.CollectionDeserializer.readList(CollectionDeserializer.java:106)
> >
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:1015)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:128)
> > at
> > com.caucho.hessian.io.JavaDeserializer.readMap(JavaDeserializer.java:105)
> > at
> > com.caucho.hessian.io.HessianInput.readObject(HessianInput.java:999)
> > at
> > com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:134)
> >
> > at
> > com.caucho.hessian.server.HessianServlet.service(HessianServlet.java:293)
> > at
> > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
> >
> > at
> > org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
> >
> > at
> > org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
> >
> > at
> > org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
> >
> > at
> > org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
> >
> > at
> > org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
> >
> > at
> > org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
> > at
> > org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
> > at
> > org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
> >
> > at
> > org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
> >
> > at
> > org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
> >
> > at
> > org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
> >
> > at java.lang.Thread.run(Thread.java:534)
> >
> >
> >
>
>

-- 
christian campo (gmail.com)