This is a question concerning what is the proper way to synchronize a shared object in java. One caveat is that the object that I want to share must be accessed from static methods. My question is, If I synchronize on a static field, does that lock the class the field belongs to similar to the way a synchronized static method would? Or, will this only lock the field itself?

In my specific example I am asking: Will calling PayloadService.getPayload() or PayloadService.setPayload() lock PayloadService.payload? Or will it lock the entire PayloadService class?

public class PayloadService extends Service {   


private static PayloadDTO payload = new PayloadDTO();


public static  void setPayload(PayloadDTO payload){
    synchronized(PayloadService.payload){
        PayloadService.payload = payload;
    }
}

public static  PayloadDTO getPayload() {
    synchronized(PayloadService.payload){
        return PayloadService.payload ;
    }
}

...

Is this a correct/acceptable approach ?

In my example the PayloadService is a separate thread, updating the payload object at regular intervals - other threads need to call PayloadService.getPayload() at random intervals to get the latest data and I need to make sure that they don't lock the PayloadService from carrying out its timer task