# How do extension functions work?

**URL:** <https://discuss.kotlinlang.org/t/how-do-extension-functions-work/609>\
**Category:** Uncategorized\
**Created:** [April 1, 2014, 11:02am UTC](https://discuss.kotlinlang.org/t/how-do-extension-functions-work/609 "2014-04-01T11:02:38Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![abreslav](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/abreslav/32/8279_2.png) [@abreslav](https://discuss.kotlinlang.org/u/abreslav)\
**Post date:** [April 1, 2014, 11:19am UTC](https://discuss.kotlinlang.org/t/how-do-extension-functions-work/609/4 "2014-04-01T11:19:42Z")

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The target classes are not modified. Extensions are visible from Java reflection as static methods in the classes they are defined in (.i.e. in package-classes for top-level extension functions).

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