What's the defference between the dependencyManagement and dependencies?

[陈思淼]

 <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>test</groupId>
        <artifactId>d</artifactId>
        <version>1.0</version>
      </dependency>
    </dependencies>
  </dependencyManagement>


  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>a</artifactId>
      <version>1.0</version>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>c</artifactId>
      <scope>runtime</scope>
    </dependency>
  </dependencies>