How do I write multiple objects to the serializable file and read them when the program is used again?

Inorder to write and read multiple objects please try as below

Writing multiple object into List

    WriteObject wo=new WriteObject(20, "Mohan");
    WriteObject wo1=new WriteObject(21, "Mohanraj");

    ArrayList<WriteObject> woi=new ArrayList<>();
    try {
        FileOutputStream fop=new FileOutputStream("c://object.ser");
        ObjectOutputStream oos=new ObjectOutputStream(fop);
        woi.add(wo);
        woi.add(wo1);
        oos.writeObject(woi);

    } catch NotFoundException e) {
}

Reading all objects from file

 try {
        FileInputStream fis=new FileInputStream("C://object.ser");
        ObjectInputStream ois=new ObjectInputStream(fis);
        WriteObject wo=null;
        WriteObject[] woj=new WriteObject[5];

        ArrayList<WriteObject> woi=new ArrayList<>();
        woi=(ArrayList<WriteObject>)ois.readObject();

        for(int i=0;i<woi.size();i++){
            woi.get(i).getvalues();
        }

Here getvalues() is method present in Writeobject class. Follow the same mechanism for your code snippet