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Neither the original array values nor the public list can be modified by a client. For more details about unmodifiable wrappers, refer to OBJ56-J. Provide sensitive mutable classes with unmodifiable wrappers. This solution can also be used when the array contains mutable objects.

Exceptions

OBJ01-J-EX0: Fields with no associated behavior or invariants can be public. According to Sun's Code Conventions document [Conventions 2009]:

One example of appropriate public instance variables is the case where the class is essentially a data structure, with no behavior. In other words, if you would have used a struct instead of a class (if Java supported struct), then it's appropriate to make the class's instance variables public.

OBJ01-J-EX1: Fields in a package-private class or in a private nested class may be pubic or protected. There is nothing inherently wrong with declaring fields to be public or protected in these cases. Eliminating accessor methods generally improves the readability of the code both in the class definition and in the client [Bloch 2008].

OBJ01-J-EX2: Static final fields that contain or reference immutable constants may be public or protected.

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