spring security stop crushed session - spring

Question

I'm using spring security for the first time and when I thought that I finished I met a problem with the spring security sessions. The scenario is when I log in with a first user and after log in with another user in another machine
if I refresh the first user, the details of the second user are displayed.
It's like the session of the 1st user is crushed by the second user and I don't understand why. There is my spring security configuration:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:sec="http://www.springframework.org/schema/security"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="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-3.2.xsd">
<sec:http auto-config="true" >
<sec:intercept-url pattern="/jsf/home.xhtml"
access="ROLE_ECRITURE, ROLE_LECTURE, ROLE_ADMIN" />
<sec:intercept-url pattern="/jsf/resultTestEligibilite_ADSL.xhtml"
access="ROLE_ECRITURE, ROLE_LECTURE, ROLE_ADMIN" />
<sec:intercept-url pattern="/jsf/resultTestEligibilite_SDSL.xhtml"
access="ROLE_ECRITURE, ROLE_LECTURE, ROLE_ADMIN" />
<sec:intercept-url pattern="/jsf/resultTestEligibilite_SDSLplus.xhtml"
access="ROLE_ECRITURE, ROLE_LECTURE, ROLE_ADMIN" />
<sec:logout invalidate-session="true"
delete-cookies="JSESSIONID"
success-handler-ref="customLogoutSuccessHandler"/>
<sec:form-login login-processing-url="/j_spring_security_check"
login-page="/index.xhtml" default-target-url="/jsf/home.xhtml"
authentication-failure-url="/index.xhtml?error=1" />
<sec:session-management invalid-session-url="/j_spring_security_logout" />
</sec:http>
<bean id="propertyConfigurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="ignoreResourceNotFound" value="true" />
<property name="ignoreUnresolvablePlaceholders" value="false" />
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="locations">
<list>
<value>
classpath:/jboss.properties
</value>
</list>
</property>
</bean>
<bean id="ldapUserSearch"
class="org.springframework.security.ldap.search.FilterBasedLdapUserSearch">
<constructor-arg index="0" value="${ldap.user-search-base}" />
<constructor-arg index="1" value="${ldap.user-search-filter}" />
<constructor-arg index="2" ref="contextSource" />
<property name="searchSubtree" value="true" />
</bean>
<bean id="contextSource"
class="org.springframework.security.ldap.DefaultSpringSecurityContextSource">
<constructor-arg value="${ldap.url}" />
<property name="userDn" value="${ldap.manager-dn}" />
<property name="password" value="${ldap.manager-password}" />
</bean>
<sec:ldap-server
url="${ldap.url}"
manager-dn="${ldap.manager-dn}"
manager-password="${ldap.manager-password}"
id = "contextSource"
root="${ldap.root}"/>
<sec:ldap-user-service id="ldapUserService"
server-ref="contextSource"
group-search-base="${ldap.group-search-base}"
group-role-attribute="${ldap.group-role-attribute}"
group-search-filter="${ldap.group-search-filter}"
user-search-base="${ldap.user-search-base}"
user-search-filter="${ldap.user-search-filter}" />
<sec:authentication-manager alias="MyManager">
<sec:ldap-authentication-provider
user-search-base="${ldap.user-search-base}"
user-search-filter="${ldap.user-search-filter}"
group-search-base="${ldap.group-search-base}"
group-search-filter="${ldap.group-search-filter}"
role-prefix="${ldap.role-prefix}"
user-context-mapper-ref="customUserDetailsMapper">
<sec:password-compare hash="{sha}" >
<sec:password-encoder ref="passwordEncoder" />
</sec:password-compare>
</sec:ldap-authentication-provider>
</sec:authentication-manager>
<bean id="passwordEncoder" class="org.springframework.security.authentication.encoding.LdapShaPasswordEncoder" >
<property name="forceLowerCasePrefix" value="true" />
</bean>
<bean id="LdapUserDetailManager"
class="org.springframework.security.ldap.userdetails.LdapUserDetailsManager">
<constructor-arg ref="contextSource" />
<property name="attributesToRetrieve" >
<list>
<value>wsEligXdslFaiUsername</value>
</list>
</property>
</bean>
<bean id="customUserDetailsMapper" class="com.axione.eligibilite.ihm.ldap.impl.CustomUserDetailsContextMapper" />
</beans>`enter code here`
Thank you in advance of your help, cause I really don't know where this problem comes from.