The final keyword can be used to specify constant values (that is, values that cannot change during program execution). However, constants that can change over the lifetime of a program should not be declared public final. The Java Language Specification [JLS 2011] allows implementations to insert the values of public final fields inline in any compilation unit that reads the field. Consequently, if the declaring class is edited so that the new version gives a different value for the field, compilation units that read the public final field could still see the old value until they are recompiled. This problem may occur, for example, when a third-party library is updated to the latest version but the referencing code is not recompiled.
A related error can arise when a programmer declares a static final reference to a mutable object; see OBJ50-JG. Never confuse immutability of a reference with that of the referenced object for additional information.
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