public interface Session {
    public String getName();
    public void setName(String name);
}

public class Websocket implements Session {
    private String name;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

public class CWebsocket implements Session {
    private Integer id;
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
}

public class Test {
    public static void main(String [] args) {
        Websocket websocket =  new Websocket();
        websocket.setName("test");

        CWebsocket cWebsocket = (CWebsocket) websocket;
        System.out.println(cWebsocket.getName());
    }
}