Differences between dependencyManagement and dependencies in Maven

Question

What is the difference between dependencyManagement and dependencies? I have seen the docs at Apache Maven web site. It seems that a dependency def

Answer 1

Sorry I am very late to the party.

Let me try to explain the difference using mvn dependency:tree command

Consider the below example

Parent POM - My Project

    app
    data



    
        com.google.guava
        guava
        19.0
    



    
        
            org.apache.commons
            commons-lang3
            3.9
        
    

Child POM - data module

    
        org.apache.commons
        commons-lang3
    

Child POM - app module (has no extra dependency, so leaving dependencies empty)

On running mvn dependency:tree command, we get following result

Scanning for projects...
------------------------------------------------------------------------
Reactor Build Order:

MyProject
app
data

------------------------------------------------------------------------
Building MyProject 1.0-SNAPSHOT
------------------------------------------------------------------------

--- maven-dependency-plugin:2.8:tree (default-cli) @ MyProject ---
com.iamvickyav:MyProject:pom:1.0-SNAPSHOT
\- com.google.guava:guava:jar:19.0:compile

------------------------------------------------------------------------
Building app 1.0-SNAPSHOT
------------------------------------------------------------------------

--- maven-dependency-plugin:2.8:tree (default-cli) @ app ---
com.iamvickyav:app:jar:1.0-SNAPSHOT
\- com.google.guava:guava:jar:19.0:compile

------------------------------------------------------------------------
Building data 1.0-SNAPSHOT
------------------------------------------------------------------------

--- maven-dependency-plugin:2.8:tree (default-cli) @ data ---
com.iamvickyav:data:jar:1.0-SNAPSHOT
+- org.apache.commons:commons-lang3:jar:3.9:compile
\- com.google.guava:guava:jar:19.0:compile

Google guava is listed as dependency in every module (including parent), whereas the apache commons is listed as dependency only in data module (not even in parent module)