Search code examples
mavendependencies

Maven dependency with type = pom


I declare in the parent POM

<dependencyManagement>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
            <scope>compile</scope>
        </dependency>
</dependencyManagement>

Further, the child pom use

<dependencies>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
</dependencies>

All work fine? but when I use such dependency with type = pom

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.jboss.spec</groupId>
                <artifactId>jboss-javaee-7.0</artifactId>
                <version>${jboss-javaee-7.0.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
</dependencyManagement>

I have error

[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]   
[ERROR]   The project by.services:by.utils:1.0.2 (D:\Work\V2_Change_Maven_Structure\by.utils\pom.xml) has 1 error
[ERROR]     'dependencies.dependency.version' for org.jboss.spec:jboss-javaee-7.0:jar is missing. @ line 18, column 21
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.

How to declare a dependency in dependencyManagement with type = pom $ {Jboss-javaee-7.0.version} announced If I bear jboss-javaee-7.0 in the root, then runs


Solution

  • The clarification here is that when you do not define <type> on your </dependency> within </dependencyManagement> it defults to jar

    <dependencyManagement>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
            <scope>compile</scope>
            <type>jar<type> <!--default value-->
        </dependency>
    </dependencyManagement>
    

    and hence the module uses that jar while using it as

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
    </dependency> 
    

    The type of dependency. This defaults to jar. While it usually represents the extension on the filename of the dependency, that is not always the case. A type can be mapped to a different extension and a classifier. The type often corresponds to the packaging used, though this is also not always the case. Some examples are jar, war, ejb-client and test-jar New types can be defined by plugins that set extensions to true, so this is not a complete list.


    But next when you explicitly declare the parent pom to have the type as

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.jboss.spec</groupId>
                <artifactId>jboss-javaee-7.0</artifactId>
                <version>${jboss-javaee-7.0.version}</version>
                <type>pom</type><!--override the default value-->
                <scope>import</scope>
            </dependency>
    </dependencyManagement>
    

    the child module now either can inherit the dependency with the same <type> as

    <dependency>
         <groupId>org.jboss.spec</groupId>
         <artifactId>jboss-javaee-7.0</artifactId>
         <type>pom</type><!--inherited-->
    </dependency>
    

    OR if you want to utilize the jar of the project which is a different <type>, you can explicitly mention the dependency as :

    <dependency>
         <groupId>org.jboss.spec</groupId>
         <artifactId>jboss-javaee-7.0</artifactId>
         <version>${jboss-javaee-7.0.version}</version>
         <type>jar</type> <!--different from parent-->
    </dependency>