Serializing a HashTable, Java

Question

I have never used Serialization before. I think I have it all right except the last part in my "Q" case-switch. ``` public class Test{ public static void main(String args[]){ Store store = new Store(); FileOutputStream fos; ObjectOutputStream oos = null; try{ fos = new FileOutputStream(new File("table.obj")); oos = new ObjectOutputStream(fos); }catch(IOException e1){ e1.printStackTrace(); } ``` This goes on to contain a bunch of more code but what I think is really important is my "Q" case... ``` case "Q": System.out.println("Good-Bye!"); try{ oos.writeObject(store); oos.flush(); oos.close(); }catch(IOException e){ e.printStackTrace(); } System.exit(0); break; ``` When I attempt to save all the data to my .obj file and close the streams and exit my program I get all these errors... java.io.NotSerializableException: Item at java.io.ObjectOutputStream.writeObject0(Unknown Source) at java.io.ObjectOutputStream.writeObject(Unknown Source) at java.util.Hashtable.writeObject(Unknown Source)…

Accepted Answer

Even if the `Hashtable` object is serializable, the objects that you are storing inside it must be serializable as well. So I would first check to see if whatever you're storing inside your `Hashtable` implements the `Serializable` interface. At the very least, your `Store` class should also implement the `Serializable` interface.

UPDATE

Based on your updated question, it looks like the `Item` class will need to implement `Serializable` as well. In fact, this is exactly what the first line of the exception says:

```
java.io.NotSerializableException: Item
```

Serializing a HashTable, Java

Solution

Problem