Error: The prefix "security" for element "security:authentication-provider" is not bound - spring

Question

Here's my application-security.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<!--
- Sample namespace-based configuration
-
- $Id: applicationContext-security.xml 3019 2008-05-01 17:51:48Z luke_t $
-->
<beans:beans xmlns="http://www.springframework.org/schema/security"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:beans="http://www.springframework.org/schema/beans"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/security
http://www.springframework.org/schema/security/spring-security-3.1.xsd">
<global-method-security secured-annotations="enabled">
</global-method-security>
<!-- Don't set any role restrictions on login.jsp -->
<intercept-url pattern="/login.jsp" access="IS_AUTHENTICATED_ANONYMOUSLY" />
<!-- Restrict access to ALL other pages -->
<intercept-url pattern="/**" access="ROLE_USER" />
<intercept-url pattern="/admin/*.html" access="ROLE_ADMIN" />
<intercept-url pattern="/manager/*.html" access="ROLE_MANAGER" />
<intercept-url pattern="/**.html" access="ROLE_USER,ROLE_ADMIN, ROLE_MANAGER" />
<!-- Set the login page and what to do if login fails -->
<form-login login-page="/login.jsp" authentication-failure-url="/login.jsp?login_error=1" default-target-url="/user/userdashboard/dashboard.html" />
<logout logout-success-url="/login.jsp"/>
</http>
<!--
Usernames/Passwords are
rod/koala
dianne/emu
scott/wombat
peter/opal
-->
**<security:authentication-provider>
<jdbc-user-service data-source-ref="dataSource" />
</security:authentication-provider>**
</beans:beans>
Everything works fine but I get this weird error of "The prefix "security" for element "security:authentication-provider" is not bound." even though I have supplied the closing tag. Anyone having any clue about how to go about this problem?

Answer 1

Either use "security" for all elements, by using the proper namespace:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:security="http://www.springframework.org/schema/security"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/security
http://www.springframework.org/schema/security/spring-security-3.0.3.xsd">
...
</beans>
And then use "security:" everywhere, for instance:
<security:global-method-security secured-annotations="enabled">
</security:global-method-security>
Or completly get rid of it:
...
<authentication-provider>
<jdbc-user-service data-source-ref="dataSource" />
</authentication-provider>
...
because you configured the default namespace xmlns="http://www.springframework.org/schema/security"