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Re: NotSerializableException

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On 4/13/2015 9:51 PM, akkshaykhoslaa@gmail.com wrote:
> Hi,
>
> My code is as follows:
>
>          File ser = new File("locationinstringform");
>          FileInputStream fileIn3 = new FileInputStream(ser);
>          ObjectInputStream objectIn3 = new ObjectInputStream(fileIn3);
>          myObj = (MyObj) objectIn3.readObject();
>          objectIn3.close();
>          fileIn3.close();
>          myObj.someFunction(x, y);
>          FileOutputStream fileOut3 = new FileOutputStream(ser);
>          ObjectOutputStream objectOut3 = new ObjectOutputStream(fileOut3);
>          objectOut3.writeObject(myObj);
>          objectOut3.close();
>          fileOut3.close();
>
> When I run my code, I get an error tracing to the line that says objectOut3.writeObject(myObj);
>
> The error is as follows:
> Exception in thread "main" java.io.NotSerializableException: java.util.HashMap$KeySet
>
> However, that MyObj class I have defined isn't a HashMap or Set, and doesn't have a HashMap or Set. It only has 2 instance objects, one of which is one is an object I coded, and the other is an ArrayList. I have made sure all classes I have coded implement the serializable interface.
>
> Any ideas as to why the problem could be arising and what the solution is? I have been stuck for a long time so any help would be much appreciated.

     Your object refers -- directly or indirectly -- to a HashMap.KeySet
instance.  You mention an ArrayList: What does that list contain?  Does
it, perhaps, hold a Set that turns out to be a HashMap.KeySet?  Or does
it hold a Thing that refers to a Widget that refers to a Whatnot that
refers to a Gizmo that refers to a HashMap.KeySet?

     Serializing an object also serializes everything the object refers
to, and everything those objects refer to, and so on through the entire
object graph.

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM

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NotSerializableException akkshaykhoslaa@gmail.com - 2015-04-13 18:51 -0700
  Re: NotSerializableException Robert Klemme <shortcutter@googlemail.com> - 2015-04-14 07:50 +0200
  Re: NotSerializableException Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-04-14 08:13 -0400

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