How do I modify an argument from the constructor in the class function itself?

Question

So, I'm coding an HTTP server in Java using HttpServer. I'm trying to implement my own session state-storing system using cookies and a session ID. The state has to be shared across all the handlers, so I initialized it in the Main file, then passed it into the class like this.

Main.java:

public class Main {
    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
        Map<String, Map<String, String>> sessionData = new HashMap<>();
        server.createContext("/test", new Handlers.SessionTestSet(sessionData));
        server.setExecutor(null); // creates a default executor
        server.start();
    }
}

And then, here's the problem. sessionD (the original object) has to be copied in order to be read by the class itself later, but I don't know if it's a shallow copy or a deep copy, and I need to modify not just sessionData , but sessionD as well. How would I modify sessionD ? I also couldn't find anything on Google so sorry if this is a duplicate. And also, clone() does not work as it is protected.

Handler.java

static class SessionTestSet implements HttpHandler {
    private Map<String, Map<String, String>> sessionData;
    public SessionTestSet(Map<String, Map<String, String>> sessionD) {
        sessionData = sessionD;
    }
    ...

Answer 1

Try this for cloning object -

    public class Employee implements Cloneable{

    private int empoyeeId;
    private String employeeName;

    public Employee(int id, String name)
    {
        this.empoyeeId = id;
        this.employeeName = name;
    }
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
    }



// Now test cloning

public class Test 
{

    public static void main(String[] args) throws CloneNotSupportedException
    {

        Employee original = new Employee(1, "Foo");

        //Lets create a clone of original object
        Employee cloned = (Employee) original.clone();

        //Let verify using employee id, if cloning actually worked
        System.out.println(cloned.getEmpoyeeId());
        //Must be true and objects must have different memory addresses
        System.out.println(original != cloned);
    }
}

For Deep cleaning you can add new class inside employee and check. Hope this will help.

Answer 2

I think I get it. Non-primitive objects are automatically shallow cloned if they are copied from the constructor using a copy constructor. Thanks for trying to help anyways!