The Author Online Book Forums are Moving

The Author Online Book Forums will soon redirect to Manning's liveBook and liveVideo. All book forum content will migrate to liveBook's discussion forum and all video forum content will migrate to liveVideo. Log in to liveBook or liveVideo with your Manning credentials to join the discussion!

Thank you for your engagement in the AoF over the years! We look forward to offering you a more enhanced forum experience.

Pradeep (3) [Avatar] Offline
#1
I am reading the section on dirty checking from the section 3.2.3 and have a doubt from the below quote
Another issue to consider is dirty checking. Hibernate automatically detects state changes in order to synchronize the updated state with the database. It’s usually safe to return a different instance from the getter method than the instance passed by Hibernate to the setter. Hibernate compares them by value—not by object identity—to determine whether the attribute’s persistent state needs to be updated. For example, the following getter method doesn’t result in unnecessary SQL UPDATEs:

public String getFirstName(){
    return new String(firstName);
}


My question is why returning a new String object will not make unecessary SQL UPDATEs and how is it different from returning just the firstName ?