Serialize

// 1º
public class User {
    public String name;
}
// Use
User u = new User();
u.name = "Daniel";
String name = u.name;

// 2º
public class User {
    public String name;
    public User(name) {
        this.name = name;
    }
}
// Use
User u = new User("Daniel");
String name = u.name;

// 3º
public class User {
    private String name;
    public void setName(String name) {
        this.name = name;
    }
    public String getName() {
        return this.name;
    }
}
// Use
User u = new User();
u.setName("Daniel");
String name = u.getName();