Re: NotSerializableException

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.