# Claim (false): Julia isn't multiple dispatch but overloading

**URL:** <https://discourse.julialang.org/t/claim-false-julia-isnt-multiple-dispatch-but-overloading/42370>\
**Category:** General Usage\
**Tags:** multidispatch\
**Created:** [July 1, 2020, 1:55pm UTC](https://discourse.julialang.org/t/claim-false-julia-isnt-multiple-dispatch-but-overloading/42370 "2020-07-01T13:55:00Z")\
**Posts on this page:** 1\
**Showing post:** 132

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**Author:** ![gbellomia](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gbellomia/32/19443_2.png) [@gbellomia](https://discourse.julialang.org/u/gbellomia)\
**Post date:** [September 23, 2022, 1:02am UTC](https://discourse.julialang.org/t/claim-false-julia-isnt-multiple-dispatch-but-overloading/42370/132 "2022-09-23T01:02:04Z")

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I think future visitors of the page may want to read this:

> [@Allocation and slow down when # of types involved increase (slower than C++ virtual methods)](https://discourse.julialang.org/t/allocation-and-slow-down-when-of-types-involved-increase-slower-than-c-virtual-methods/87656/3):
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> Dynamic dispatch is slow in Julia — slower than C++ virtual methods, because C++ method dispatch only depends on a single object type (this) and hence can use [vtable](https://en.wikipedia.org/wiki/Virtual_method_table) lookup. High-performance code in Julia always relies on devirtualizing critical code. This also means that you can’t easily write performant geometry code in Julia by having an array of geometric objects of different types and relying on dynamic dispatch to execute different methods (determined at runtime) for different objects —…

Reason is in my honest opinion the true sentiment of the original claim and the push force of frequent recurrent revival is that: yes, Julia semantics are inherently dynamic but everytime you need performance (which is a very strong selling point for the language), you need to make sure the actual behavior can be devirtualized, effectively reconciling with static overloading.

Ideally I would post this even under the celebrated YouTube video (The unreasonable…), but YouTube has no good facilities for screenshot embedding or nice external link rendering 🙂

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