春季安全会议管理

Question

I want to know about this code clearly.Can somebody explain me please?

com / nhfIa.png

<beans:bean id="sas" class="org.springframework.security.web.authentication.session.CompositeSessionAuthenticationStrategy">
    <beans:constructor-arg>
        <beans:list>
            <beans:bean
                        class="org.springframework.security.web.authentication.session.ConcurrentSessionControlAuthenticationStrategy">
                <beans:constructor-arg ref="sessionRegistry"/>
                <beans:property name="maximumSessions" value="1" />
                <beans:property name="exceptionIfMaximumExceeded" value="true" />
            </beans:bean>
            <beans:bean
                        class="org.springframework.security.web.authentication.session.SessionFixationProtectionStrategy">
            </beans:bean>
            <beans:bean
                        class="org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy">
                <beans:constructor-arg ref="sessionRegistry"/>
            </beans:bean>
        </beans:list>
    </beans:constructor-arg>
</beans:bean>
<beans:bean id="sessionRegistry" class="org.springframework.security.core.session.SessionRegistryImpl"/>