---
layout: pattern
title: Mutex
folder: mutex
permalink: /patterns/mutex/
pumlid: 9SR13OCm30NGLSe0n7UsCS62LB69x6zWV2hrdTxKhFRS9Br_3c34GkHybxtXo3L3l9u6CPHwAhMUDuETldpnl4cqtUR1WBW5ASSlf0bvI53_A-bQHcf_0G00
categories: Concurrency
tags: 
 - Java
 - Difficulty-Intermediate
---

## Also known as
Mutual Exclusion Lock
Binary Semaphore

## Intent
Create a lock which only allows a single thread to access a resource at any one instant.

![alt text](./etc/mutex.png "Mutex")

## Applicability
Use a Mutex when

* you need to prevent two threads accessing a critical section at the same time
* concurrent access to a resource could lead to a race condition 

## Credits

* [Lock (computer science)] (http://en.wikipedia.org/wiki/Lock_(computer_science))
* [Semaphores] (http://tutorials.jenkov.com/java-concurrency/semaphores.html)