Final (Java): Difference between revisions

Revision as of 01:13, 30 May 2013

Revision as of 21:53, 27 June 2013

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== Final methods ==

A '''final [[Method (computer science)|method]]''' cannot be [[Method overriding|overridden]] or hidden by subclasses.<ref>[http://docs.oracle.com/javase/specs/jls/se7/html/jls-8.html#jls-8.4.3.3]</ref> This is used to prevent unexpected behavior from a subclass altering a method that may be crucial to the function or consistency of the class.<ref>[http://java.sun.com/docs/books/tutorial/java/IandI/final.html Writing Final Classes and Methods]</ref>

Example:

<source lang="java">

public class MyClassBase
{

public void myMethodm1() {...}

public final void myFinalMethodm2() {...}

}

public classstatic AnotherClass extendsvoid MyClassm3() {...}

public static final void myMethodm4() {...} // Ok

public final void myFinalMethod() {...} // forbidden

}

public class Derived extends Base

{

public void m1() {...} // Ok, overriding Base#m1()

public void m2() {...} // forbidden

public static void m3() {...} // OK, hiding Base#m3()

public finalstatic void myFinalMethodm4() {...} // forbidden

}

</source>