The true definition of immutability?

Question

I am wondering how immutability is defined? If the values aren\'t exposed as public, so can\'t be modified, then it\'s enough?

Can the values be modified inside the type

Answer 1

The definition of immutability can be located on Google .

Example:

immutable - literally, not able to change.
www.filosofia.net/materiales/rec/glosaen.htm

In terms of immutable data structures, the typical definition is write-once-read-many, in other words, as you say, once created, it cannot be changed.

There are some cases which are slightly in the gray area. For instance, .NET strings are considered immutable, because they can't change, however, StringBuilder internally modifies a String object.