How to write and read java serialized objects into a file

Why not serialize the whole list at once?

FileOutputStream fout = new FileOutputStream("G:\\address.ser");
ObjectOutputStream oos = new ObjectOutputStream(fout);
oos.writeObject(MyClassList);

Assuming, of course, that MyClassList is an ArrayList or LinkedList, or another Serializable collection.

In the case of reading it back, in your code you ready only one item, there is no loop to gather all the item written.

As others suggested, you can serialize and deserialize the whole list at once, which is simpler and seems to comply perfectly with what you intend to do.

In that case the serialization code becomes

ObjectOutputStream oos = null;
FileOutputStream fout = null;
try{
    fout = new FileOutputStream("G:\\address.ser", true);
    oos = new ObjectOutputStream(fout);
    oos.writeObject(myClassList);
} catch (Exception ex) {
    ex.printStackTrace();
} finally {
    if(oos != null){
        oos.close();
    } 
}

And deserialization becomes (assuming that myClassList is a list and hoping you will use generics):

ObjectInputStream objectinputstream = null;
try {
    FileInputStream streamIn = new FileInputStream("G:\\address.ser");
    objectinputstream = new ObjectInputStream(streamIn);
    List<MyClass> readCase = (List<MyClass>) objectinputstream.readObject();
    recordList.add(readCase);
    System.out.println(recordList.get(i));
} catch (Exception e) {
    e.printStackTrace();
} finally {
    if(objectinputstream != null){
        objectinputstream .close();
    } 
}

You can also deserialize several objects from a file, as you intended to:

ObjectInputStream objectinputstream = null;
try {
    streamIn = new FileInputStream("G:\\address.ser");
    objectinputstream = new ObjectInputStream(streamIn);
    MyClass readCase = null;
    do {
        readCase = (MyClass) objectinputstream.readObject();
        if(readCase != null){
            recordList.add(readCase);
        } 
    } while (readCase != null)        
    System.out.println(recordList.get(i));
} catch (Exception e) {
    e.printStackTrace();
} finally {
    if(objectinputstream != null){
        objectinputstream .close();
    } 
}

Please do not forget to close stream objects in a finally clause (note: it can throw exception).

EDIT

As suggested in the comments, it should be preferable to use try with resources and the code should get quite simpler.

Here is the list serialization :

try(
    FileOutputStream fout = new FileOutputStream("G:\\address.ser", true);
    ObjectOutputStream oos = new ObjectOutputStream(fout);
){
    oos.writeObject(myClassList);
} catch (Exception ex) {
    ex.printStackTrace();
}