CODEWITHSUNDEEP
javamaven-2
Helfdane
Helfdane

Reputation: 113

dependency not found at runtime maven

I'm new to maven and somewhat new to java. Tried google and related sources, but I didn't find one which resembled my situation.

Right now, I have maven project X and Y. X can be seen as a shared library with some utilities, Y is a simple JFrame with a "hello world" printed and a call to a static method in X.

I do a "run as maven install" on project X, I get a "build successful". I add project X as dependency in project Y (using the pom-editor in Eclipse, browsing the repository and locating it). I do a "run as maven package" on project Y, I get a "build successful". Upon running project Y either via java -jar or inspect the produced jar, project X is missing everywhere and I get a fancy class not found exception. Eclipse finds it and there are no compile errors in the source editor.

Why is it only working in the Eclipse editor and not as jar?

POM:

    <dependency>
        <groupId>com.company.deployment.shared</groupId>
        <artifactId>com.company.deployment.shared</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <scope>compile</scope>
    </dependency>

Upvotes: 7

Views: 19157

Answers (6)

David
David

Reputation: 1458

Phil Sacre already explained the basic problem well (there basically is just no information on where to find the X.jar embedded in your Y.jar).

Additionally you can also look at the appassembler-maven-plugin (which can e.g. generate launch scripts for your Y project that already have the right classpath set) and/or the exec-maven-plugin (which you can use to e.g. directly launch Y with the right classpath using maven).

Upvotes: 0

Adrian Shum
Adrian Shum

Reputation: 40036

The artifact produced in project Y contains only build results in project Y only, not including its dependencies.

If you want to build a JAR in Y, which u can execute directly, you can consider using assembly plugin.

For example, the easiest way to build a uber-jar for project Y:

<project>
  ...
  <build>
    ...
    <plugins>
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>2.2.1</version>
        <configuration>
          <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
          </descriptorRefs>
        </configuration>
        <executions>
          <execution>
            <id>make-all-in-one-jar</id>
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
            ...
</project>

Apart from a normal artifact, an assembly which contains classes etc from dependencies will be created, which is suitable to be executed by java -jar

visit http://maven.apache.org/plugins/maven-assembly-plugin/ for more sophisticated usage.

Upvotes: 0

Prashant Bhate
Prashant Bhate

Reputation: 11087

You may also find exec-maven-plugin helpful

mvn exec:java -Dexec.mainClass="com.example.Main" [-Dexec.args="argument1"] ...
mvn exec:exec -Dexec.executable="maven" [-Dexec.workingdir="/tmp"] -Dexec.args="-X myproject:dist"

If your client can not download dependencies from maven m2 repo on the fly like behind firewall or no internet connection, then you also need to package the dependencies using maven-dependency-plugin to copy all dependencies and maven-assembly-plugin to assemble dependencies

Upvotes: 1

Stephen C
Stephen C

Reputation: 718826

I recommend that you take a look at the Maven shade plugin. This produces an "uber-jar" comprising your project and all of its dependencies. It can also do other things such as setting the entry point class to make your JAR file an executable JAR.

Upvotes: 2

JB Nizet
JB Nizet

Reputation: 691745

It doesn't work because Maven resolves dependencies when building your project, but doesn't put all the dependencies magically in your jar. You're supposed to run your app with all its dependencies in the classpath:

java -classpath X.jar;Y.jar com.foo.bar.Main

Or you have to customize the maven jar plugin in order to create an executable jar, as described here. And you may also use the maven assemby plugin to copy all your Y project's dependencies to the target directory, next to the generated Y.jar.

Upvotes: 0

user7094
user7094

Reputation:

Maven doesn't produce a combined JAR file for you. What Eclipse is doing is looking at the Maven configuration and adding all the required classes / jars to your classpath for you when it runs.

If you want to run your program from the command-line, you will need to add all the JARs manually to your classpath.

Alternatively, you could run your program directly from Maven which should set up all your dependencies. There are a number of options depending on what you want to do, i.e. if it's an application which is meant to be run by an end-user you could look into the one-jar Maven plugin.

Upvotes: 7

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