How to serialize a generic class in Java?

Question

I have started to read about serialization in Java and little bit in other languages too, but what if I have a generic class and I want to save a instance of it to file.

Answer 1

If you don't want (or cannot) implement the Serializable interface, you can use XStream. Here is a short tutorial.

In your case:

XStream xstream = new XStream();
Generic<T> generic = ...;//whatever needed
String xml = xstream.toXML(generic);
//write it to a file (or use xstream directly to write it to a file)

Answer 2

You need to make generic class Serializable as usual.

public class Generic<T> implements Serializable {...}

If fields are declared using generic types, you may want to specify that they should implement Serializable.

public class Generic<T extends Serializable> implements Serializable {...}

Please be aware of uncommon Java syntax here.

public class Generic<T extends Something & Serializable> implements Serializable {...}