The introduction of the three-party jar package control in MAVEN engineering a little knowledge of the introduced version

<Projectxmlns= "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>Com.demo.wx</groupId>  <Artifactid>Wx</Artifactid>  <Packaging>War</Packaging>  <version>0.0.1-snapshot</version>  <name>WX Maven Webapp</name>  <URL>http://maven.apache.org</URL>  <Properties>    <!--Spring Version number -    <spring.version>4.1.2.RELEASE</spring.version>    <!--mybatis Version number -    <mybatis.version>3.2.6</mybatis.version>    <!--log4j log File Management Pack version -    <slf4j.version>1.7.7</slf4j.version>    <log4j.version>1.2.17</log4j.version>  </Properties>  <Dependencies>
        <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-core</Artifactid>              <version>${spring.version}</version>          </Dependency>            <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-web</Artifactid>              <version>${spring.version}</version>          </Dependency>          <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-oxm</Artifactid>              <version>${spring.version}</version>          </Dependency>          <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-tx</Artifactid>              <version>${spring.version}</version>          </Dependency>            <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-jdbc</Artifactid>              <version>${spring.version}</version>          </Dependency>            <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-webmvc</Artifactid>              <version>${spring.version}</version>          </Dependency>          <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-aop</Artifactid>              <version>${spring.version}</version>          </Dependency>            <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-context-support</Artifactid>              <version>${spring.version}</version>          </Dependency>            <Dependency>              <groupId>Org.springframework</groupId>              <Artifactid>Spring-test</Artifactid>              <version>${spring.version}</version>          </Dependency>          <Dependency>              <groupId>Org.mybatis</groupId>              <Artifactid>MyBatis</Artifactid>              <version>${mybatis.version}</version>          </Dependency>         <Dependency>              <groupId>Log4j</groupId>              <Artifactid>Log4j</Artifactid>              <version>${log4j.version}</version>          </Dependency>                    <Dependency>              <groupId>Org.slf4j</groupId>              <Artifactid>Slf4j-api</Artifactid>              <version>${slf4j.version}</version>          </Dependency>            <Dependency>              <groupId>Org.slf4j</groupId>              <Artifactid>Slf4j-log4j12</Artifactid>              <version>${slf4j.version}</version>          </Dependency>            </Dependencies>  <Build>    <Finalname>Wx</Finalname>  </Build></Project>

The defined version number is declared in <properties> </properties> so that the managed version doesn't mess up.

The introduction of the three-party jar package control in MAVEN engineering a little knowledge of the introduced version