I have a hobby project, which is basically to maintain 'todo' tasks in the way I like. One task can be described as:

public class TodoItem {
    private String subject;
    private Date dueBy;
    private Date startBy;
    private Priority priority;
    private String category;
    private Status status;
    private String notes;
}

As you can imagine I would have 1000s of todo items at a given time.

• What is the best strategy to store a todo item? (currently on an XML file) such that all the items are loaded quickly up on app start up(the application shows kind of a dashboard of all the items at start up)?
• What is the best way to design its back-end so that it can be ported to Android/or a J2ME based phone?
• Currently this is done using Java Swing. What should I concentrate on so that it works efficiently on a device where memory is limited?
• The application throws open a form to enter new todo task. For now, I would like to save the newly added task to my-todos.xml once the user presses "save" button. What are the common ways to append such a change to an existing XML file?(note that I don't want to read the whole file again and then persist)