Final (Java): Difference between revisions

Revision as of 18:52, 4 September 2017

Revision as of 18:53, 4 September 2017

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In the [[Java (programming language)|Java programming language]], the <code>'''final'''</code> [[Keyword (computing)|keyword]] is used in several different contexts to define an entity that can only be assigned once.

Once a <code>'''final'''</code> variable has been assigned, it always contains the same value. If a <code>'''final'''</code> variable holds a reference to an object, then the state of the object may be changed by operations on the object, but the variable will always refer to the same object (this property of <code>'''final'''</code> is called ''non-transitivity''<ref>{{cite journal|last1=Coblenz|first1=Michael|last2=Sunshine|first2=Joshua|last3=Aldrich|first3=Jonathan|last4=Myers|first4=Brad|last5=Weber|first5=Sam|last6=Shull|first6=Forrest|title=Exploring Language Support for Immutability|journal=The 38th International Conference on Software Engineering|date=14{{ndash}}22 May 2016}}</ref>). This applies also to arrays, because arrays are objects; if a <code>'''final'''</code> variable holds a reference to an array, then the components of the arra°°°°°°yarray may be changed by operations on the array, but the variable will always refer to the same array.<ref>Java Language Specification #4.12.4</ref>

==Final classes==