jython-users

[Jython-users] Serializable classes

[Ranjan B. <ran...@fr...>]

Hi --

Is there any magic I need to do to make Jython objects deserialize correctly?  I was experimenting with having a Jython class implement Serializable -- to be honest, I expected to see it blow up when I sent it to an ObjectOutputStream -- but that worked.

However, when I deserialize it, I get a ClassNotFound exception.

Here's the code:

import java
class MyClass(java.io.Serializable):
    def __init__(this, x):
        this.x = x

obj = MyClass(33)
baos = java.io.ByteArrayOutputStream()
oos = java.io.ObjectOuputStream(baos)
oos.writeObject(obj)
## good so far
ois = java.io.ObjectInputStream(java.io.ByteArrayInputStream(baos.toByteArray()))
ois.readObject()
Traceback (innermost last):
  File "<console>", line 1, in ?
java.lang.ClassNotFoundException: org.python.proxies.__main__$MyClass$0
        at java.net.URLClassLoader$1.run(URLClassLoader.java:201)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:189)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:308)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:264)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:324)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:212)
        at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:546)
        at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1491)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1413)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1604)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1252)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:323)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:42)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:28)
        at java.lang.reflect.Method.invoke(Method.java:313)
        at org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java
)
        at org.python.core.PyMethod.__call__(PyMethod.java)
        at org.python.core.PyObject.__call__(PyObject.java)
        at org.python.core.PyInstance.invoke(PyInstance.java)
        at org.python.pycode._pyx11.f$0(<console>:1)
        at org.python.pycode._pyx11.call_function(<console>)
        at org.python.core.PyTableCode.call(PyTableCode.java)
        at org.python.core.PyCode.call(PyCode.java)
        at org.python.core.Py.runCode(Py.java)
        at org.python.core.Py.exec(Py.java)
        at org.python.util.PythonInterpreter.exec(PythonInterpreter.java)
        at org.python.util.InteractiveInterpreter.runcode(InteractiveInterpreter.java)
        at org.python.util.InteractiveInterpreter.runsource(InteractiveInterpreter.java)
        at org.python.util.InteractiveInterpreter.runsource(InteractiveInterpreter.java)
        at org.python.util.InteractiveConsole.push(InteractiveConsole.java)
        at org.python.util.InteractiveConsole.interact(InteractiveConsole.java)
        at org.python.util.jython.main(jython.java)

java.lang.ClassNotFoundException: java.lang.ClassNotFoundException: org.python.proxies.__main__$MyClass$0


Any hints -- my suspicion is that it's something deep in the java security mechanism...

Ranjan

Re: [Jython-users] Serializable classes

[Samuele P. <ped...@bl...>]

Hi.

You should use a org.python.util.PythonObjectInputStream to read that back.
Anyway it is important that your class is defined at the top-level
in a module that is not the main module (that one you pass
on the jython command line),

 this are basicly the same rules
for pickle, which OTOH does not support even under jython
java classes and not completely python subclasses of java
classes.

regards, Samuele Pedroni.


----- Original Message -----
From: Ranjan Bagchi <ran...@fr...>
To: <jyt...@li...>
Sent: Sunday, January 27, 2002 5:32 AM
Subject: [Jython-users] Serializable classes


> Hi --
>
> Is there any magic I need to do to make Jython objects deserialize correctly?
I was experimenting with having a Jython class implement Serializable -- to be
honest, I expected to see it blow up when I sent it to an ObjectOutputStream --
but that worked.
>
> However, when I deserialize it, I get a ClassNotFound exception.
>
> Here's the code:
>
> import java
> class MyClass(java.io.Serializable):
>     def __init__(this, x):
>         this.x = x
>
> obj = MyClass(33)
> baos = java.io.ByteArrayOutputStream()
> oos = java.io.ObjectOuputStream(baos)
> oos.writeObject(obj)
> ## good so far
> ois =
java.io.ObjectInputStream(java.io.ByteArrayInputStream(baos.toByteArray()))
> ois.readObject()
> Traceback (innermost last):
>   File "<console>", line 1, in ?
> java.lang.ClassNotFoundException: org.python.proxies.__main__$MyClass$0
>         at java.net.URLClassLoader$1.run(URLClassLoader.java:201)
>         at java.security.AccessController.doPrivileged(Native Method)
>         at java.net.URLClassLoader.findClass(URLClassLoader.java:189)
>         at java.lang.ClassLoader.loadClass(ClassLoader.java:308)
>         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
>         at java.lang.ClassLoader.loadClass(ClassLoader.java:264)
>         at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:324)
>         at java.lang.Class.forName0(Native Method)
>         at java.lang.Class.forName(Class.java:212)
>         at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:546)
>         at
java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1491)
>         at
java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1413)
>         at
java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1604)
>         at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1252)
>         at java.io.ObjectInputStream.readObject(ObjectInputStream.java:323)
>         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>         at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:42)
>         at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.ja
va:28)
>         at java.lang.reflect.Method.invoke(Method.java:313)
>         at
org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java
> )
>         at org.python.core.PyMethod.__call__(PyMethod.java)
>         at org.python.core.PyObject.__call__(PyObject.java)
>         at org.python.core.PyInstance.invoke(PyInstance.java)
>         at org.python.pycode._pyx11.f$0(<console>:1)
>         at org.python.pycode._pyx11.call_function(<console>)
>         at org.python.core.PyTableCode.call(PyTableCode.java)
>         at org.python.core.PyCode.call(PyCode.java)
>         at org.python.core.Py.runCode(Py.java)
>         at org.python.core.Py.exec(Py.java)
>         at org.python.util.PythonInterpreter.exec(PythonInterpreter.java)
>         at
org.python.util.InteractiveInterpreter.runcode(InteractiveInterpreter.java)
>         at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpreter.java)
>         at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpreter.java)
>         at org.python.util.InteractiveConsole.push(InteractiveConsole.java)
>         at
org.python.util.InteractiveConsole.interact(InteractiveConsole.java)
>         at org.python.util.jython.main(jython.java)
>
> java.lang.ClassNotFoundException: java.lang.ClassNotFoundException:
org.python.proxies.__main__$MyClass$0
>
>
> Any hints -- my suspicion is that it's something deep in the java security
mechanism...
>
> Ranjan
>
>
>
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> https://lists.sourceforge.net/lists/listinfo/jython-users
>