Explain the Three Benefits of Access Protection ?

Access protection has three major benefits:
1. It permits you to enforce constraints on an object's state.
2. It gives a simpler client interface. Client programmers don't require knowing everything that's in the class, only the public elements.
3. It separates interface from implementation, permitting them to vary independently. For example consider making the licensePlate field of Car an instance of a new LicensePlate class instead of a String.