If a Serializable class contains a member that is not serializable, then when an attempt is made to serialize the object, a java.io.NotSerializableException will be thrown. This is because the serialization mechanism needs to serialize all members of the class, including any member variables.
To fix this issue, there are a few options:
- Make the member variable transient: By marking the non-serializable member variable as transient, it will be excluded from the serialization process, and its value will not be saved or restored. This is a good option if the member variable is not critical to the state of the object, or if it can be easily recreated.
- Make the member variable serializable: If the non-serializable member variable is an object that can be made Serializable, then you can modify the class definition of that object to implement the Serializable interface.
- Implement custom serialization methods: If neither of the above options is possible, you can implement custom serialization methods in the Serializable class to manually serialize and deserialize the non-serializable member variable. This involves implementing the writeObject() and readObject() methods, which provide custom serialization and deserialization logic for the class.
Overall, the best approach will depend on the specific requirements of the application and the nature of the non-serializable member variable.