Any Difference on synchronize whole and parts?

Question

I want to know any difference between two codes:
Code 1
public class Client {
  private Model model=new Model();
  public synchronized int getId() {
    return model.getId();
  public static void main(String argv) {
    Client c=new Client();
    System.out.println(c.getId());
public class Model {
  private int id=1;
  public synchronized int getId() {
    return id;
Code 2
public class Client {
  private Model model=new Model();
  public synchronized Model getModel() {
    return model;
  public static void main(String argv) {
    Client c=new Client();
    System.out.println(c.getModel().getId());
public class Model {
  private int id=1;
  public synchronized int getId() {
    return id;
}Is Code 2 more risky?
Because my model has a lot of methods, i don't want to rewrite every one on the client. Please comment two codes!
Thank you!
Leo Tai

Answer 1

Code 1 is redundant and would also affect performance to some degree.
Code 2 is better than Code 1.
If there are no setting methods on Client for setting the model, then you may also remove the synchronized keyword from getModel(). Avoid synchronizing methods if there is no use for it.
If id is an int then the synchronized on getId can also be removed.
Assignment to variables of any simple type except long or double is atomic. You don't have to worry about a thread preempting a method in the middle of the assignment. In practice, this means that you never have to synchronize a method that does nothing but return the value of (or assign a value to) a boolean or int instance variable.
Regards,
Tarun