I've recently added Apache Commons IO to a small project of mine so that I can tail a log file. Everything works great in my IDE (IntelliJ), but when I create the executable jar, Commons IO isn't in there, so I get :
Exception in thread "main" java.lang.NoClassDefFoundError:
org/apache/commons/io/input/TailerListener.
Commons IO has been added to my POM:
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.1</version>
</dependency>
I've never had issues with added dependencies like this before. What am I missing?
That's not exactly how dependencies work. Dependencies are just there to tell other projects what to pull in. They don't become automatically included in your jar.
The reason for this is because it's wasteful under certain circumstances. Imagine you have two jars: a.jar and b.jar. Both rely on apache commons. It would probably be more efficient (space-wise) to simply have each separated and loaded from a common library directory.
If you want a so-called "fat jar" (or whatever the proper term for having all of your dependencies in one jar is), you need to use a plugin like this one:
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2.1</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>com.test.App</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
Related
I have a jar project that uses some .jar libs to run. In old days we use Eclipse to build the jar, but now my company is migrating to Maven. I didn't know how hard is to create an independent jar file that contains its dependencies (or some of them) inside itself like before xD.
I've read that there's an "assembly" maven plugin that "unpack" the dependencies and put them inside the independent jar, but my company has its own maven repository and they don't have that plugin. So, I'm using the "dependency-plugin" to achieve that.
The problem is that I can't get my independent jar to run.
I have this in my pom:
...
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>.</classpathPrefix>
<mainClass>jar.App</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.2</version>
<executions>
<execution>
<id>copy</id>
<phase>package</phase>
<goals>
<goal>copy</goal>
</goals>
</execution>
</executions>
<configuration>
<artifactItems>
<artifactItem>
<groupId>com.example.jar2</groupId>
<artifactId>jar2</artifactId>
<version>1.0-SNAPSHOT</version>
<type>jar</type>
<overWrite>false</overWrite>
<outputDirectory>${project.build.directory}/classes</outputDirectory>
</artifactItem>
</artifactItems>
<outputDirectory>${project.build.directory}/classes</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>true</overWriteSnapshots>
</configuration>
</plugin>
<plugin>
Actually, the content of the pom.xml is not important because I get what I wanted: my jar with a structure like this:
jar1.jar
|
- com/something/my-classes.class
|
- META-INF
| |
| - MANIFEST
| - maven
| |
| - A lot of maven stuffs
|
- jar2-1.0-SNAPSHOT.jar
And my MANIFEST file has these entries:
Class-Path: ./jar2-1.0-SNAPSHOT.jar
Main-Class: jar.App
I thought it was enough to have my jar dependencies copied inside my independent jar and indicate the Class-Path in my MANIFEST to tell to java "hey! here are my dependencies!", but, when I try to run the jar with:
java -jar my-jar.jar
I get:
Exception in thread "main" java.lang.NoClassDefFoundError: jar2/Operations
In the line where I'm trying to use the classes of my dependencies.
Why is that? What I need to get an independent jar with Maven (without using the assambly plugin)? I supposed I'm missing something to indicate to Java where my dependencies are, but I'm not sure... Or maybe I need an extra class that "loads" every class that I'm using?
Thanks a lot!
I used simplejavamail in my maven project. The program can send out the email if I run it from Intellij IDE. But when I create a jar file, and run it from the jar file, then I got class not found for all the simplejavamail classes. And I open the jar, I find out that they are not included in the jar. But all the other dependency classes are there. Any one have meet this issue before?
parts of my pom.xml
<dependency>
<groupId>org.simplejavamail</groupId>
<artifactId>simple-java-mail</artifactId>
<version>6.4.3</version>
</dependency>
<build>
<finalName>my-project-name</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
I'm having the same problem. It appears that the dependencies (Ex. Email, Mailer, EmailBuilder, etc) appear in the org.simplejavamail.api repository. I'll update you if I find a working solution with v6.4.3 but I have a feeling we may need to include additional dependencies.
Edit: To at least patch your problem,
<dependency>
<groupId>org.simplejavamail</groupId>
<artifactId>simple-java-mail</artifactId>
<version>5.5.1</version>
</dependency>
The 5.5.1 version still has the classes in the jar. You can reference this for yourself here:
https://www.javadoc.io/doc/org.simplejavamail/simple-java-mail/5.5.1/index.html
Then click on the different versions to see what classes exist.
I think something went wrong in their builds since v6.
Let me know if this helps!
The following reference mentions the descriptor Reference jar-with-dependencies. Afaik it is a predefined assembly, which includes all jar dependencies into a single big self-contained jar file. This is great if you have multiple dependencies and need to copy your project to another machine because you don't need to update/delete obsolete libraries separately.
https://newfivefour.com/category_maven-assembly.html
I added the maven-assembly-plugin to my pom, and the MyTool.jar-with-dependency.jar is created. I expected that the jar contains all external dependencies, but it is the same as the normal MyTool.jar and does not contain any dependencies like apache.commons or apache.logging.
The important detail is that the dependencies scope is set to provided. Without this it works as expected. But I use the scope later on with the maven-dependency-plugin to copy all dependencies in the provided scope to a specific directory.
[...]
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.5</version>
<scope>privided</scope>
</dependency>
</dependencies>
<build>
<!--pluginManagement-->
<plugins>
<plugin> <!-- This is the plugin I added. -->
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
[...]
I use Apache Maven 2.2.1 (rdebian-14).
How can I include the dependencies from the provided scope? Or is there an other solution?
I have a multimodule Maven project with several dependencies. I want to build a fat executable JAR containing them as well as my own compiled classes. I found maven-assembly-plugin to be just what I needed except one nasty problem.
Some of my dependencies are local and distributed with project sources. I use system scope for them. It looks something like this:
<dependency>
<groupId>com.intellij</groupId>
<artifactId>forms_rt</artifactId>
<version>1</version>
<scope>system</scope>
<systemPath>${project.basedir}/lib/forms_rt.jar</systemPath>
</dependency>
The problem is that for some reason these libraries aren't unpacked and bundled with the rest of dependencies in result JAR.
I know that usage of system scope is considered bad practice, and in fact I even can find some of them (though quite outdated) in Maven repositories, but anyway it puzzles me how it can be solved with maven-assembly-plugin.
Just in case my plugin configuration looks like this:
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>repoll.server.Repoll</mainClass>
</manifest>
</archive>
<finalName>${project.build.finalName}-full</finalName>
<appendAssemblyId>false</appendAssemblyId>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
As I understood I have to write custom descriptor, which e.g. includes and unpacks all JARs from ${project.basedir}/lib directory, but after several unsuccessful attempts I still don't know how to do so.
I've managed to find solution here. It's described in this question.
In short, the whole problem was in usage of system scope. It turned out, that such dependencies are filtered out by default, which I found out by running mvn package with debug output enabled (-X/--debug).
When local repository is defined for these JARs, distributed with project, they are unpacked by maven-assembly-plugin as exepected.
I'm building a service which contains a client module which is using Spring. The service which will be implementing the client does not contain spring but it has a dependency on the client which has dependencies on Spring. Ideally I would like the client to include the needed Spring dependencies in the JAR but I can't seem to figure out how to accomplish this. I've seen a few different examples of using maven-assembly-plugin but I would prefer to not have to use something other than "mvn clean package" to accomplish this.
Any help is appreciated.
The maven-shade-plugin allows you to build an uber-jar containing some (or all) of your dependencies. It should allow you to do what you need.
By binding the assembly plugin's single goal to the project's build lifecycle, you can accomplish what you want by running mvn clean package.
Cut/pasting the pom configuration to do this from the usage page of the plugin,
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2.2</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
[...]
</project>
Of course, you would tweak either either to use a different predefined descriptor or even use a separate descriptor file.