CODEWITHSUNDEEP
mavenjdbcdependency-management
Coderer
Coderer

Reputation: 27264

Maven dependency:analyze thinks my JDBC JARs are "unused"

I'm using a MySQL connector JAR to make JDBC connections. My understanding is that I just have this JAR in the classpath, and it'll be dynamically loaded when I specify mysql: in the connection string.

I declare this dependency in my POM using <scope>runtime</scope>. When I run mvn dependency:analyze, it reports this artifact as "unused". I guess it can't determine that I'll need it through simple static analysis, fine, but surely that's going to be true of just about any runtime-scoped artifact, right? How can I convince Maven that this artifact really needs to be there?

Upvotes: 4

Views: 2217

Answers (1)

Pace
Pace

Reputation: 43817

dependency:tree will list all artifacts that are referenced by your pom files if that is what you are looking for. Otherwise you are likely out of luck. Maven openly declares that their dependency analyzer works at the bytecode level and will falsely report dependencies as unused in some scenarios.

A runtime-scoped dependency may or may not be used, it is impossible to tell with bytecode analysis (in fact, impossible to tell with most analysis I could think of). Maven has to decide to either assume they are used or assume they are unused and they went with the latter figuring the user could figure it out.

There is no option to tell Maven to treat runtime-scoped dependencies as used but you can manually add specific artifacts to the usedDependencies array in the configuration. Maven will simply assume those dependencies are used. You could also write your own dependency analyzer or find a 3rd party dependency analyzer that can handle this scenario.

==Update for comments==

You're right, it is quite new. The issue was fixed in version 2.6 which was released Nov, 25, 2012. It isn't yet in many of the public mirror repositories. You can find it here.

Since it is so new there are no examples of its usage however Maven follows some conventions. I would expect it to be declared as:

<build>
    <plugins>
     <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>2.6</version>
        <configuration>
          <usedDependencies>
            <usedDependency>org.foo.bar:baz-tron</usedDependency>
            <usedDependency>org.foo:whatsit</usedDependency>
          </usedDependencies>
        </configuration>
      </plugin>
    </plugins>
  </build>

Upvotes: 4

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