Unable to create a new instance of 'org.springframework.web.jsf.el.SpringBeanFacesELResolver

For a large time, my application works correctly, But I got this new exception in running of application now:

java.lang.RuntimeException: com.sun.faces.config.ConfigurationException: 
  Source Document: jndi:/localhost/OBS2/WEB-INF/faces-config.xml
  Cause: Unable to create a new instance of 

'org.springframework.web.jsf.el.SpringBeanFacesELResolver': javax.faces.FacesException: org.springframework.web.jsf.el.SpringBeanFacesELResolver
    at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:280)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4992)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5492)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:672)
    at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:547)
    at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1670)
    at sun.reflect.GeneratedMethodAccessor300.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1480)
    at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:882)
    at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:368)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:612)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2462)
    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2451)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.sun.faces.config.ConfigurationException: 
  Source Document: jndi:/localhost/OBS2/WEB-INF/faces-config.xml
  Cause: Unable to create a new instance of 'org.springframework.web.jsf.el.SpringBeanFacesELResolver': javax.faces.FacesException: org.springframework.web.jsf.el.SpringBeanFacesELResolver
    at com.sun.faces.config.processor.AbstractConfigProcessor.createInstance(AbstractConfigProcessor.java:353)
    at com.sun.faces.config.processor.ApplicationConfigProcessor.addELResolver(ApplicationConfigProcessor.java:604)
    at com.sun.faces.config.processor.ApplicationConfigProcessor.process(ApplicationConfigProcessor.java:305)
    at com.sun.faces.config.processor.AbstractConfigProcessor.invokeNext(AbstractConfigProcessor.java:152)
    at com.sun.faces.config.processor.LifecycleConfigProcessor.process(LifecycleConfigProcessor.java:116)
    at com.sun.faces.config.processor.AbstractConfigProcessor.invokeNext(AbstractConfigProcessor.java:152)
    at com.sun.faces.config.processor.FactoryConfigProcessor.process(FactoryConfigProcessor.java:239)
    at com.sun.faces.config.ConfigManager.initialize(ConfigManager.java:435)
    at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:221)
    ... 44 more
Caused by: javax.faces.FacesException: org.springframework.web.jsf.el.SpringBeanFacesELResolver
    at com.sun.faces.config.processor.AbstractConfigProcessor.loadClass(AbstractConfigProcessor.java:384)
    at com.sun.faces.config.processor.AbstractConfigProcessor.createInstance(AbstractConfigProcessor.java:278)
    ... 52 more
Caused by: java.lang.ClassNotFoundException: org.springframework.web.jsf.el.SpringBeanFacesELResolver
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:344)
    at com.sun.faces.util.Util.loadClass(Util.java:325)
    at com.sun.faces.config.processor.AbstractConfigProcessor.loadClass(AbstractConfigProcessor.java:376)
    ... 53 more

faces-config.xml:

<?xml version='1.0' encoding='UTF-8'?>
<faces-config version="2.2"
              xmlns="http://ift.tt/19L2NlC"
              xmlns:xsi="http://ift.tt/ra1lAU"
              xsi:schemaLocation="http://ift.tt/19L2NlC
                http://ift.tt/1mXF9WB">

    <application>
        <message-bundle>JsfMessages</message-bundle>
    </application>

    <!-- JSF and Spring are integrated -->
    <application>
        <el-resolver>org.springframework.web.jsf.el.SpringBeanFacesELResolver</el-resolver>
    </application>

</faces-config>

I am integrating spring+jsf+hibernate frameworks.

faces-config is under WEB-INF directory.

pom.xml:

<dependencies>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>4.3.1.Final</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish</groupId>
        <artifactId>javax.faces</artifactId>
        <version>2.2.7</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
    <dependency>
        <groupId>dom4j</groupId>
        <artifactId>dom4j</artifactId>
        <version>1.6.1</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate.javax.persistence</groupId>
        <artifactId>hibernate-jpa-2.1-api</artifactId>
        <version>1.0.0.Final</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.3.6.Final</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.3</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-oxm</artifactId>
        <version>3.2.7.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.primefaces</groupId>
        <artifactId>primefaces</artifactId>
        <version>5.0</version>
    </dependency>
    <dependency>
        <groupId>commons-dbcp</groupId>
        <artifactId>commons-dbcp</artifactId>
        <version>1.4</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-api</artifactId>
        <version>2.1.7</version>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-impl</artifactId>
        <version>2.1.7</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>javassist</groupId>
        <artifactId>javassist</artifactId>
        <version>3.12.1.GA</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aspects</artifactId>
        <version>3.2.7.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.7.2</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>3.2.7.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>4.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>1.2.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>6.0</version>
        <scope>provided</scope>
    </dependency>

</dependencies>

Every thing is good, why should this happen?