Re: Exception in Hessian Serialization

I worked it out.

File Transfers don't work in hessian.

The fact that it did work is strange, but kind-of makes sense. I was
testing on my dev machine and running the server locally, so the File
handle pointed to the same location on the hard drive.

I have actually ended up bypassing Hessian for file transfer in the end
- we already had a mechanism for sending very large files, so I have
used that instead (the files being sent by hessian were actually icons,
so thought i could get away wityh it).

Thanks for your help though.

Christian Campo wrote:

>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)
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>

-- 
Toby Hede
Software Engineer
Web Alive Technologies Pty Ltd
The OSSI Group Pty Ltd
Level 1, Innovation Building
Digital Harbour, 1010 La Trobe Street
Melbourne VIC 3000
P: +61 3 9934 0888
F: +61 3 9934 0899
E: toby.hede@xxx.biz
W: www.webalive.biz
 
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