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Solution for a jar file not findable in the `WEB-INF/lib` folder nor `src/main/resources` folder?

Answer 1

+2 A:

<dependency>
    <groupId>org.companyname</groupId>
    <artifactId>artifact</artifactId>
    <version>versionNumber</version>
    <scope>system</scope>
    <systemPath>PATH_TO_YOUR_JAR</systemPath>
</dependency>

Try something like this

Dependencies with the scope system are always available and are not looked up in repository. They are usually used to tell Maven about dependencies which are provided by the JDK or the VM. Thus, system dependencies are especially useful for resolving dependencies on artifacts which are now provided by the JDK, but where available as separate downloads earlier. Typical example are the JDBC standard extensions or the Java Authentication and Authorization Service (JAAS).

A simple example would be:

<project>
  ...
  <dependencies>
    <dependency>
      <groupId>javax.sql</groupId>
      <artifactId>jdbc-stdext</artifactId>
      <version>2.0</version>
      <scope>system</scope>
      <systemPath>${java.home}/lib/rt.jar</systemPath>
    </dependency>
  </dependencies>
  ...
</project>

Resource

org.life.java 2010-10-26 16:25:30

Thanks. But as I mentioned to @axtavt in the comment above, I want to remove them from the pom because even though they are in my local Maven repository, while maven is building the project it always says it is trying to download each of these local dependencies, adding extra time onto each build cycle. I was hoping to copy these jars to a location where they will be found by the build process but without Maven trying to download any resources each time.

wiki 2010-10-26 16:31:44

@wiki, Try this conf. it won't download as maven is instructed to refer from system Path itself

org.life.java 2010-10-26 16:35:05

@wiki you can also use `-o` flag to instruct maven to build in offline mode forcefully

org.life.java 2010-10-26 16:37:49

Works perfectly! Thank you!

wiki 2010-10-26 16:52:02

@wiki you did it with -o or the conf. above ?

org.life.java 2010-10-26 16:53:44

I did it with `-o` but I'm trying it the other way now.

wiki 2010-10-26 17:04:34

ok.. keep us updated

org.life.java 2010-10-26 17:04:58

You've used `<systemPath>${java.home}/lib/rt.jar</systemPath>` in the example above. So what I'm not sure about is how to define a variable like `${java.home}` that will work locally to identify `${application-root}/WEB-INF/lib` as well as after I deploy it to app engine. How would it know what `${application-root}` is unless it's an absolute directory location - something I can't define on app engine. (Assuming I move these Maven repository jars to `${application-root}/WEB-INF/lib`)

wiki 2010-10-26 17:15:30

@wiki it is given from that link resources, It is simply env variable

org.life.java 2010-10-27 06:57:44

Answer 2

+2 A:

As I mentioned in a comment below, I want to remove them from the pom because even though they are in my local Maven repository, while maven is building the project it always says it is trying to download each of these local dependencies, adding extra time onto each build cycle.

You aren't showing any trace illustrating the exact problem (this usually helps) but unless your local dependencies are SNAPSHOT dependencies (and that would be a bad choice for manually installed artifacts), I don't think your description of the behavior is accurate.

I was hoping to copy these jars to a location where they will be found by the build process but without Maven trying to download any resources each time.

My guess is that the dependencies are just missing a .pom file, which is what Maven is trying to download. You can tell Maven to generate this pom for you when installing a JAR in your local repository using:

mvn install:install-file -Dfile=your-artifact-1.0.jar \
                         [-DgroupId=org.some.group] \
                         [-DartifactId=your-artifact] \
                         [-Dversion=1.0] \
                         [-Dpackaging=jar] \
                         [-DgeneratePom=true]

Regardless of how horrible it may seem, I find Maven's behavior here more horrible.

Using system scope dependencies doesn't seem horrible, it is an horrible and discouraged practice and should be avoided in 99,999% of the cases. Quoting the provided link:

system: This dependency is required in some phase of your project's lifecycle, but is system-specific. Use of this scope is discouraged: This is considered an "advanced" kind of feature and should only be used when you truly understand all the ramifications of its use, which can be extremely hard if not actually impossible to quantify. This scope by definition renders your build non-portable. It may be necessary in certain edge cases. The system scope includes the <systemPath> element which points to the physical location of this dependency on the local machine. It is thus used to refer to some artifact expected to be present on the given local machine an not in a repository; and whose path may vary machine-to-machine. The systemPath element can refer to environment variables in its path: ${JAVA_HOME} for instance.

Just use Maven the right way and you won't have problems. With system scoped dependencies (why on earth people keep suggesting to abuse them?!), I predict more troubles later.

As you correctly guessed, the htmlunit that is in my local maven repository does not have pom files. I also can't remember how I installed it.

So I'm not crazy :) Obviously, my suggestion is to fix the problem and to provide the missing .pom files. If you don't want to reinstall the artifacts (so that Maven could generate them), you can create the .pom manually. A simple file like this would suffice:

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>ze.groupId</groupId>
  <artifactId>some-artifact-id</artifactId>
  <version>X.Y.Z</version>
</project>

But please, don't switch to system scoped dependencies, this will do more harm than good on the long run.

You may be asking why I am using version 2.8 - well, it contains some patches that are essential for my project.

You certainly have good reasons and I won't even discuss them.

(...) I get an error during the build that says "command line too long":

That's unfortunate, and you should report this problem to datanucleus.

Pascal Thivent 2010-10-26 19:27:15

@Pascal: Thanks for your impassioned response. This is how I had installed each of the gdata jars: `mvn install:install-file -DgroupId=gdata -DartifactId=base -Dversion=1.0 -Dfile=gdata-base-1.0.jar -Dpackaging=jar -DgeneratePom=true`. As you see, it did generate poms and I can verify that after checking the install directory. Unfortunately I can't reproduce the original problem for you at this very moment so I understand your frustration at not seeing the original trace.

wiki 2010-10-26 19:37:50

@wiki Then my guess was wrong. But if you can post a trace later, I'll have a look and update my answer. And trust me, using the `system` scope is not a good "solution" and I'll do my best to provide an alternative.

Pascal Thivent 2010-10-26 19:43:44

@Pascal: I appreciate it. I have updated the question with some additional information.

wiki 2010-10-26 21:50:50

@wiki Thanks for posting the trace and confirming I was on the right track.

Pascal Thivent 2010-10-26 23:09:09

@Pascal: I will reinstall the artifacts so that Maven can generate the poms. Thanks for explaining.

wiki 2010-10-27 00:03:02

@wiki You're welcome. Glad it helped. And don't forget, every time you use a system scoped dependency, God kills a Maven developer :)

Pascal Thivent 2010-10-27 00:40:08

Thanks pascal for letting me know this.

org.life.java 2010-10-27 07:03:57

@Pascal: That seems like a disproportionate response on God's part.

wiki 2010-10-27 11:55:11

@wiki Hmm... That's just a joke around the "God kills a kitten" meme.

Pascal Thivent 2010-10-27 16:25:56

@Pascal: I know. I was joking too :) Everything works perfectly now by the way. Thanks again!

wiki 2010-10-27 17:46:42

@wiki Ohh, I think I got it... now ;)

Pascal Thivent 2010-10-27 18:44:50

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Solution for a jar file not findable in the `WEB-INF/lib` folder nor `src/main/resources` folder?

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