invariant object

• 不变对象

invariant object的用法和样例：

例句

1. If the key was a mutable object, its value could be changed.
   如果键是可变对象，它的值可改变。
2. Classes in the Java class library are examples of immutable objects - they represent a single value that cannot change over the lifetime of the object.
   类就是不变对象的示例它们表示在对象的生命期内无法更改的单个值。