title: In a Maven multi-module project, how to specify dependency needed in more than one module?
body: <p>I know that the intent of a multi-module Maven project is that each module can be compiled and built separately as well as collectively from the parent.</p>
  
  <p>Suppose two of my <a href="https://vaadin.com/maven#archetypes" rel="nofollow noreferrer">three modules</a> need to use the <a href="https://en.wikipedia.org/wiki/Google_Guava" rel="nofollow noreferrer">Google Guava</a> library. Do I specify that dependency in the POM of each of the two sub-modules? If so, what “scope”? Or do I specify the dependency in the parent module? I need Guava bundled in my final product, but I certainly don't need two copies. </p>