i want to use the addon vaadin Timeline, so i have to make "gwt-maven-plugin 3.1" as i know ,my pom.xml is the following : <?xml version="1.0"?> <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>life</groupId> <artifactId>life</artifactId> <packaging>war</packaging> <name>life Portlet</name> <version>0.0.1-SNAPSHOT</version> <url>http://maven.apache.org</url> <properties> <vaadin-widgets-dir>src/main/webapp/VAADIN/widgetsets</vaadin-widgets-dir> </properties> <build> <plugins> <plugin> <groupId>com.liferay.maven.plugins</groupId> <artifactId>liferay-maven-plugin</artifactId> <version>6.1.0</version> <configuration> <autoDeployDir>${liferay.auto.deploy.dir}</autoDeployDir> <liferayVersion>6.1.0</liferayVersion> <pluginType>portlet</pluginType> </configuration> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <encoding>UTF-8</encoding> <source>1.5</source> <target>1.5</target> </configuration> </plugin> <plugin> <groupId>com.vaadin</groupId> <artifactId>vaadin-maven-plugin</artifactId> <version>1.0.1</version> </plugin> <!-- Compiles your custom GWT components with the GWT compiler --> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>gwt-maven-plugin</artifactId> <version>2.1.0-1</version> <configuration> <!-- if you don't specify any modules, the plugin will find them --> <!--modules> .. </modules --> <webappDirectory>${project.build.directory}/${project.build.finalName}/VAADIN/widgetsets</webappDirectory> <extraJvmArgs>-Xmx512M -Xss1024k</extraJvmArgs> <runTarget>clean</runTarget> <hostedWebapp>${project.build.directory}/${project.build.finalName}</hostedWebapp> <noServer>true</noServer> <port>8080</port> <soyc>false</soyc> </configuration> <executions> <execution> <goals> <goal>resources</goal> <goal>compile</goal> </goals> </execution> </executions> </plugin> <!-- Updates Vaadin 6.2+ widgetset definitions based on project dependencies --> <plugin> <groupId>com.vaadin</groupId> <artifactId>vaadin-maven-plugin</artifactId> <version>1.0.1</version> <executions> <execution> <configuration> <!-- if you don't specify any modules, the plugin will find them --> <!-- <modules> <module>${package}.gwt.MyWidgetSet</module> </modules> --> </configuration> <goals> <goal>update-widgetset</goal> </goals> </execution> </executions> </plugin> </plugins> <pluginManagement> <plugins> <!--This plugin's configuration is used to store Eclipse m2e settings only. It has no influence on the Maven build itself. --> <plugin> <groupId>org.eclipse.m2e</groupId> <artifactId>lifecycle-mapping</artifactId> <version>1.0.0</version> <configuration> <lifecycleMappingMetadata> <pluginExecutions> <pluginExecution> <pluginExecutionFilter> <groupId> org.codehaus.mojo </groupId> <artifactId> gwt-maven-plugin </artifactId> <versionRange> [2.1.0-1,) </versionRange> <goals> <goal>resources</goal> </goals> </pluginExecutionFilter> <action> <ignore></ignore> </action> </pluginExecution> <pluginExecution> <pluginExecutionFilter> <groupId>com.vaadin</groupId> <artifactId> vaadin-maven-plugin </artifactId> <versionRange> [1.0.1,) </versionRange> <goals> <goal> update-widgetset </goal> </goals> </pluginExecutionFilter> <action> <ignore></ignore> </action> </pluginExecution> </pluginExecutions> </lifecycleMappingMetadata> </configuration> </plugin> </plugins> </pluginManagement> </build> <dependencies> <dependency> <groupId>com.liferay.portal</groupId> <artifactId>portal-service</artifactId> <version>6.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.liferay.portal</groupId> <artifactId>util-bridges</artifactId> <version>6.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.vaadin.addons</groupId> <artifactId>vaadin-timeline-agpl-3.0</artifactId> <version>1.2.4</version> </dependency> <dependency> <groupId>com.liferay.portal</groupId> <artifactId>util-taglib</artifactId> <version>6.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>com.liferay.portal</groupId> <artifactId>util-java</artifactId> <version>6.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.portlet</groupId> <artifactId>portlet-api</artifactId> <version>2.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.4</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.0</version> <scope>provided</scope> </dependency> <!-- sqx --> <dependency> <groupId>javax.activation</groupId> <artifactId>activation</artifactId> <version>1.1.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>antlr</groupId> <artifactId>antlr</artifactId> <version>2.7.6</version> <scope>provided</scope> </dependency> <dependency> <groupId>aopalliance</groupId> <artifactId>aopalliance</artifactId> <version>1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>asm</groupId> <artifactId>asm</artifactId> <version>1.5.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>asm</groupId> <artifactId>asm-attrs</artifactId> <version>1.5.3</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>1.6.8</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.6.8</version> <scope>provided</scope> </dependency> <dependency> <groupId>bsh</groupId> <artifactId>bsh</artifactId> <version>1.3.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>2.1_3</version> <scope>provided</scope> </dependency> <dependency> <groupId>commons-collections</groupId> <artifactId>commons-collections</artifactId> <version>3.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>commons-dbcp</groupId> <artifactId>commons-dbcp</artifactId> <version>1.3</version> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>commons-pool</groupId> <artifactId>commons-pool</artifactId> <version>1.5.3</version> </dependency> <dependency> <groupId>dom4j</groupId> <artifactId>dom4j</artifactId> <version>1.6.1</version> </dependency> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> <version>1.2.3</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>3.3.1.GA</version> </dependency> <dependency> <groupId>hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>1.8.0.10</version> </dependency> <!-- <dependency> <groupId>jboss</groupId> <artifactId>jboss-backport-concurrent</artifactId> <version>2.1.0.GA</version> </dependency> --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-parent</artifactId> <version>1.5.0</version> </dependency> <dependency> <groupId>javax.jcr</groupId> <artifactId>jcr</artifactId> <version>1.0</version> </dependency> <!-- <dependency> <groupId>javax.sql</groupId> <artifactId>jdbc-stdext</artifactId> <version>2.0</version> </dependency> --> <dependency> <groupId>jdom</groupId> <artifactId>jdom</artifactId> <version>1.0</version> </dependency> <dependency> <groupId>javax.transaction</groupId> <artifactId>jta</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.14</version> </dependency> <dependency> <groupId>javax.mail</groupId> <artifactId>mail</artifactId> <version>1.4.3</version> </dependency> <dependency> <groupId>com.sun.portal.portletcontainer</groupId> <artifactId>container</artifactId> <version>1.1-m4</version> </dependency> <dependency> <groupId>postgresql</groupId> <artifactId>postgresql</artifactId> <version>8.4-702.jdbc3</version> </dependency> <!-- sl4j-api-1.5.0 manquante --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-parent</artifactId> <version>1.5.0</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.5.0</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>3.0.3.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jms</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>javax.jms</groupId> <artifactId>jms</artifactId> <version>1.1</version> <scope>compile</scope> </dependency> <!-- <dependency> <groupId>org.springmodules</groupId> <artifactId>spring-modules-jbpm31</artifactId> <version>0.9</version> <scope>provided</scope> </dependency> --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework.ws</groupId> <artifactId>spring-oxm</artifactId> <version>1.5.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.security</groupId> <artifactId>spring-security-core</artifactId> <version>2.0.4</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>2.5.6</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc-portlet</artifactId> <version>2.5</version> </dependency> <dependency> <groupId>com.atomikos</groupId> <artifactId>transactions-hibernate3</artifactId> <version>3.6.4</version> </dependency> <dependency> <groupId>com.atomikos</groupId> <artifactId>transactions-osgi</artifactId> <version>3.7.0</version> </dependency> <dependency> <groupId>com.vaadin</groupId> <artifactId>vaadin</artifactId> <version>6.7.0</version> </dependency> <dependency> <groupId>com.thoughtworks.xstream</groupId> <artifactId>xstream</artifactId> <version>1.3.1</version> </dependency> <!-- this is the dependency to the "jar"-subproject --> <dependency> <groupId>org.codehaus.plexus</groupId> <artifactId>plexus-utils</artifactId> <version>1.5.9</version> </dependency> <dependency> <groupId>com.google.gwt</groupId> <artifactId>gwt-user</artifactId> <version>2.1.1</version> <scope>provided</scope> </dependency> </dependencies> <!-- Define our plugin repositories --> <pluginRepositories> <pluginRepository> <id>Codehaus</id> <name>Codehaus Maven Plugin Repository</name> <url>http://repository.codehaus.org/org/codehaus/mojo</url> <snapshots> <enabled>true</enabled> </snapshots> </pluginRepository> <pluginRepository> <id>codehaus-snapshots</id> <url>[http://nexus.codehaus.org/snapshots]</url> <snapshots> <enabled>true</enabled> </snapshots> <releases> <enabled>false</enabled> </releases> </pluginRepository> </pluginRepositories> <repositories> <repository> <id>vaadin-addons</id> <url>http://maven.vaadin.com/vaadin-addons</url> </repository> <repository> <id>demoiselle.sourceforge.net</id> <name>Demoiselle Maven Repository</name> <url>http://demoiselle.sourceforge.net/repository/release</url> </repository> </repositories> AND when i do "clean install" to build my mvn , the console show me this taken : [INFO] Unable to find resource 'org.codehaus.mojo:gwt-maven-plugin:jar:1.3-SNAPSHOT' in repository demoiselle.sourceforge.net (http://demoiselle.sourceforge.net/repository/release) [INFO] ------------------------------------------------------------------------ [ERROR] BUILD ERROR [INFO] ------------------------------------------------------------------------ [INFO] Failed to resolve artifact. Missing: ---------- 1) org.codehaus.mojo:gwt-maven-plugin:jar:1.3-SNAPSHOT Try downloading the file manually from the project website. Then, install it using the command: mvn install:install-file -DgroupId=org.codehaus.mojo -DartifactId=gwt-maven-plugin - Dversion=1.3-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file Alternatively, if you host your own repository you can deploy the file there: mvn deploy:deploy-file -DgroupId=org.codehaus.mojo -DartifactId=gwt-maven-plugin -Dversion=1.3-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id] Path to dependency: 1) com.vaadin:vaadin-maven-plugin:maven-plugin:1.0.1 2) org.codehaus.mojo:gwt-maven-plugin:jar:1.3-SNAPSHOT ---------- 1 required artifact is missing. for artifact: com.vaadin:vaadin-maven-plugin:maven-plugin:1.0.1 from the specified remote repositories: demoiselle.sourceforge.net (http://demoiselle.sourceforge.net/repository/release), central (http://repo1.maven.org/maven2), Codehaus (http://repository.codehaus.org/org/codehaus/mojo), codehaus-snapshots ([http://nexus.codehaus.org/snapshots]), vaadin-snapshots (http://oss.sonatype.org/content/repositories/vaadin-snapshots/), vaadin-releases (http://oss.sonatype.org/content/repositories/vaadin-releases/), vaadin-addons (http://maven.vaadin.com/vaadin-addons) your help will be welcome thank you a lot !!! :)))