Q:

Maven for simple web app (Tomcat 7)

I try to write first maven web app with jsf.  And I faced with problem.  I try to find the answer. Every deploy I get next stack trace
java.lang. NullPointerException
    com.sun.faces.context.flash. ELFlash.getPhaseMapForReading(ELFlash.java:736)
    com.sun.faces.context.flash. ELFlash.isEmpty(ELFlash.java:465)
    com.sun.faces.facelets.util. DevTools.writeVariables(DevTools.java:318)
    com.sun.faces.facelets.util. DevTools.writeVariables(DevTools.java:208)
    com.sun.faces.facelets.util. DevTools.debugHtml(DevTools.java:123)
    com.sun.faces.renderkit. RenderKitUtils.renderHtmlErrorPage(RenderKitUtils.java:1139)
    com.sun.faces.context. ExceptionHandlerImpl.throwIt(ExceptionHandlerImpl.java:249)
    com.sun.faces.context. ExceptionHandlerImpl.handle(ExceptionHandlerImpl.java:136)
    com.sun.faces.lifecycle. Phase.doPhase(Phase.java:119)
    com.sun.faces.lifecycle. LifecycleImpl.render(LifecycleImpl.java:139)
    javax.faces.webapp. FacesServlet.service(FacesServlet.java:311)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.12 logs. 

My pom 
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> 
    <modelVersion>4.0.0</modelVersion>
    <groupId>by.bsuir.transport</groupId>
    <artifactId>transportApp</artifactId>
    <packaging>war</packaging>

    <version>1.0-SNAPSHOT</version>

    <properties>
    <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java-version>1.6</java-version>
    </properties>

    <repositories>
    <repository>
        <id>prime-repo</id>
        <name>PrimeFaces Maven Repository</name>
        <url>http://repository.primefaces.org</url>
        <layout>default</layout>
    </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>6.0</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.myfaces.core</groupId>
            <artifactId>myfaces-api</artifactId>
            <version>2.1.10</version>
        </dependency>

        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>6.0</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.primefaces</groupId>
            <artifactId>primefaces</artifactId>
            <version>3.5</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                    <compilerArguments>
                        <endorseddirs>${endorsed.dir}</endorseddirs>
                    </compilerArguments>
                </configuration>
            </plugin>
            <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.1.1</version>
            </plugin>
        </plugins>

    </build>
</project>

My web.xml
<? xml version="1.0" encoding="UTF-8"? >
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         id="WebApp_ID" version="3.0" metadata-complete="true">
    <welcome-file-list>
        <welcome-file>index.xhtml</welcome-file>
    </welcome-file-list>
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp. FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>
    <context-param>
        <param-name>javax.faces. PROJECT_STAGE</param-name>
        <param-value>Development</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces. DEFAULT_SUFFIX</param-name>
        <param-value>.xhtml</param-value>
    </context-param>
    <context-param>
        <param-name>facelets. SKIP_COMMENTS</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces. FACELETS_VIEW_MAPPINGS</param-name>
        <param-value>.xhtml</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces. DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces. STATE_SAVING_METHOD</param-name>
        <param-value>client</param-value>
    </context-param>
    <context-param>
        <param-name>org.apache.myfaces. ALLOW_JAVASCRIPT</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>org.apache.myfaces. AUTO_SCROLL</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>org.apache.myfaces. DETECT_JAVASCRIPT</param-name>
        <param-value>false</param-value>
    </context-param>
    <context-param>
        <param-name>org.apache.myfaces. PRETTY_HTML</param-name>
        <param-value>true</param-value>
    </context-param>
</web-app>

What can be the reason of this problem&

A:

I change dependencies and it works
<dependencies>

        <dependency>
            <groupId>org.apache.myfaces.core</groupId>
            <artifactId>myfaces-api</artifactId>
            <version>2.1.10</version>
        </dependency>

        <dependency>
            <groupId>org.apache.myfaces.core</groupId>
            <artifactId>myfaces-impl</artifactId>
            <version>2.1.10</version>
        </dependency>

        <dependency>
            <groupId>org.primefaces</groupId>
            <artifactId>primefaces</artifactId>
            <version>3.5</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

