Editing Virtual method table (section)

==Comparison with alternatives==
The virtual method table is generally a good performance trade-off to achieve dynamic dispatch, but there are alternatives, such as [[binary tree dispatch]], with higher performance in some typical cases, but different trade-offs.<ref name=inria-00565627 /><ref>Zendra, Olivier and Driesen, Karel, [http://www.usenix.org/event/jvm02/full_papers/zendra/zendra_html/index.html "Stress-testing Control Structures for Dynamic Dispatch in Java"], pp. 105–118, Proceedings of the USENIX 2nd Java Virtual Machine Research and Technology Symposium, 2002 (JVM '02)</ref>

However, virtual method tables only allow for [[single dispatch]] on the special "this" parameter, in contrast to [[multiple dispatch]] (as in [[Common Lisp Object System|CLOS]], [[Dylan (programming language)|Dylan]], or [[Julia (programming language)|Julia]]), where the types of all parameters can be taken into account in dispatching.

Virtual method tables also only work if dispatching is constrained to a known set of methods, so they can be placed in a simple array built at compile time, in contrast to [[duck typing]] languages (such as [[Smalltalk]], [[Python (programming language)|Python]] or [[JavaScript]]).

Languages that provide either or both of these features often dispatch by looking up a string in a [[hash table]], or some other equivalent method. There are a variety of techniques to make this faster (e.g., [[String interning|interning]]/tokenizing method names, caching lookups, [[just-in-time compilation]]).