Maven - Dependency folders inside a lib directory in Jar [duplicate] - java

I am using Maven in my standalone application, and I want to package all the dependencies in my JAR file inside a library folder, as mentioned in one of the answers here:
How can I create an executable JAR with dependencies using Maven?
I want my final JAR file to have a library folder that contains the dependencies as JAR files, not like what the maven-shade-plugin that puts the dependencies in the form of folders like the Maven hierarchy in the .m2 folder.
Well, actually the current configuration does what I want, but I am having a problem with loading the JAR files when running the application. I can't load the classes.
Here's my configuration:
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/classes/lib</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>com.myapp.MainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>install</id>
<phase>install</phase>
<goals>
<goal>sources</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>2.5</version>
<configuration>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
The project runs fine from Eclipse, and the JAR files are put in the library folder inside my final JAR file as I want, but when running the final JAR file from the target folder I always get ClassNotFoundException:
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/context/ApplicationContext
Caused by: java.lang.ClassNotFoundException: org.springframework.context.ApplicationContext
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: com.myapp.MainClass. Program will exit.
How can I fix this exception?

The following is my solution. Test it if it works for you:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/classes/lib</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<!-- <classpathPrefix>lib</classpathPrefix> -->
<!-- <mainClass>test.org.Cliente</mainClass> -->
</manifest>
<manifestEntries>
<Class-Path>lib/</Class-Path>
</manifestEntries>
</archive>
</configuration>
</plugin>
The first plugin puts all dependencies in the target/classes/lib folder, and the second one includes the library folder in the final JAR file, and configures the Manifest.mf file.
But then you will need to add custom classloading code to load the JAR files.
Or, to avoid custom classloading, you can use "${project.build.directory}/lib, but in this case, you don't have dependencies inside the final JAR file, which defeats the purpose.
It's been two years since the question was asked. The problem of nested JAR files persists nevertheless. I hope it helps somebody.

Updated:
<build>
<plugins>
<plugin>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<phase>install</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>

The simplest and the most efficient way is to use an uber plugin like this:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
<configuration>
<finalName>uber-${project.artifactId}-${project.version}</finalName>
</configuration>
</plugin>
You will have de-normalized all in one JAR file.

The executable packer maven plugin can be used for exactly that purpose: creating standalone java applications containing all dependencies as JAR files in a specific folder.
Just add the following to your pom.xml inside the <build><plugins> section (be sure to replace the value of mainClass accordingly):
<plugin>
<groupId>de.ntcomputer</groupId>
<artifactId>executable-packer-maven-plugin</artifactId>
<version>1.0.1</version>
<configuration>
<mainClass>com.example.MyMainClass</mainClass>
</configuration>
<executions>
<execution>
<goals>
<goal>pack-executable-jar</goal>
</goals>
</execution>
</executions>
</plugin>
The built JAR file is located at target/<YourProjectAndVersion>-pkg.jar after you run mvn package. All of its compile-time and runtime dependencies will be included in the lib/ folder inside the JAR file.
Disclaimer: I am the author of the plugin.

following this link:
How To: Eclipse Maven install build jar with dependencies
i found out that this is not workable solution because the class loader doesn't load jars from within jars, so i think that i will unpack the dependencies inside the jar.

Here´s how I do it:
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2</version>
<configuration>
<appendAssemblyId>false</appendAssemblyId>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>com.project.MainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
And then I just run:
mvn assembly:assembly

I found this answer to the question:
http://padcom13.blogspot.co.uk/2011/10/creating-standalone-applications-with.html
Not only do you get the dependent lib files in a lib folder, you also get a bin director with both a unix and a dos executable.
The executable ultimately calls java with a -cp argument that lists all of your dependent libs too.
The whole lot sits in an appasembly folder inside the target folder. Epic.
=============
Yes I know this is an old thread, but it's still coming high on search results so I thought it might help someone like me.

This is clearly a classpath problem. Take into consideration that the classpath must change a bit when you run your program outside the IDE. This is because the IDE loads the other JARs relative to the root folder of your project, while in the case of the final JAR this is usually not true.
What I like to do in these situations is build the JAR manually. It takes me at most 5 minutes and it always solves the problem. I do not suggest you do this. Find a way to use Maven, that's its purpose.

Related

How to run a jar with lib?

I have this jar file 'domain-directory-configurator-cli-3.1.3000.0.0.0.jar' that doesn't contain dependancies
I have also this file 'domain-directory-configurator-cli-3.1.3000.0.0.0-lib.zip'
I want to run the jar file and my application using the libs.
What is the current syntax?
I tried
java -cp 3.1.3000.0.0.0/domain-directory-configurator-cli-3.1.3000.0.0.0.jar com.imperva.itp.directory.configurator.cli.MainClass
but I keep getting the exception :
Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
so how do I refer the jar to work with the lib file?
You can do this by using the maven plugin maven-assembly-plugin
https://maven.apache.org/plugins/maven-assembly-plugin/usage.html
http://tutorials.jenkov.com/maven/maven-build-fat-jar.html
Assuming domain-directory-configurator-cli-3.1.3000.0.0.0-lib.zip does contain a number of jar files, you would have to extract themand list them one by one on the classpath.
More user friendly would be to have an executable jar where the main class is already mentioned in the manifest. Note you can configure the classpath in the manifest as well,so for a uer it could be sufficient to run java -jar domain-directory-configurator-cli-3.1.3000.0.0.0.jar and both the main class and the classpath are taken from the manifest.
In case you are using Maven, the below combination can help. It downloads all dependencies into the lib directory and configures both the main class and the classpath into the project's jar file.
<project>
<build>
<plugins>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.2.0</version>
<configuration>
<archive>
<manifest>
<addDefaultEntries>true</addDefaultEntries>
<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>com.imperva.itp.directory.configurator.cli.MainClass</mainClass>
</manifest>
<manifestEntries>
<Build-Date>$(enf.BUILD_DATE)</Build-Date>
<Build-Date-Formatted>$(enf.BUILD_DATE_FORMATTED)</Build-Date-Formatted>
</manifestEntries>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Finally, when distributing your application do not forget to deliver not only your jar but also the lib directory with content.

How can I launch the main class lying in a maven module, starting from the project itself?

If I have a project with maven folders, one of them contains the main class that should be launched (and can be launched from there), how should I make Eclipse and Maven to launch that class when I choose Run as - Java Application from the head folder?
Edit:
The maven-exec-plugin does not help:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.1.1</version>
<executions>
<execution>
<goals>
<goal>java</goal>
</goals>
<configuration>
<mainClass>use_annotations.UseAnnotationsLaunch</mainClass>
</configuration>
</execution>
</executions> </plugin>
Does not show any errors, but the head project cannot launch use_annotations.UseAnnotationsLaunch.main. I am getting "Selection does not contain a main type"
Notice, that Maven compile command calls compile for maven modules correctly. It is the problem of eclipse and maven modules.
Eclipse and Maven are using their own classpath/run configuration if I recall correctly, so you can use Eclipse's run config or you can setup maven-exec-plugin in your pom.xml and set up your run configuration to call maven.
If your classpath is set correctly using Eclipse's built-in 'Run' may be more comfortable, but using Maven run configuration will ensure your project is set up correctly if you wanted to compile and run it on other machine.
Here's a setup from my old project, there are both exec plugin and jar-with-dependencies (executable jar). Please don't mind plugin versions...
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.1.1</version>
<executions>
<execution>
<phase>deploy</phase>
<goals>
<goal>java</goal>
</goals>
<configuration>
<mainClass>my.old.project.package.gui.MainWindow</mainClass>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>my.old.project.package.gui.MainWindow</mainClass>
</manifest>
</archive>
<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>

eclipse source folder containing images doesn't export to JAR

I have written a Java program, when it is run I add the name of every image file in the folder "items" into an ArrayList.
This is fine when I am running the application in eclipse.
But as soon as I export to a runnable JAR file and run it, the images can't be found and returns a NullPointerException.
I've tried to use getClass().getResource() but to no avail.
This is what my Package Explorer looks like and
This is what my exported JAR looks like
As you can see from the second image, all the images are taken out of the items folder and left in the root of the JAR.
Any help would be greatly appreciated!
try maven-assembly-plugin if you are using the maven build tool
How can I create an executable JAR with dependencies using Maven?
https://www.mkyong.com/maven/create-a-fat-jar-file-maven-assembly-plugin/
Put this in your pom.xml
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.6</version>
<configuration>
<archive>
<manifest>
<mainClass>com.maven.class... (Class path)</mainClass>
</manifest>
</archive>
<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>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>

How do I make IntelliJ IDEA automatically extract a dependency to the artifact jar?

Let's say I'm adding the following dependency to my pom.xml:
<dependency>
<groupId>org.ini4j</groupId>
<artifactId>ini4j</artifactId>
<version>0.5.4</version>
</dependency>
I can now use the Ini class as expected, but if I try to build the jar and run it, it will give me a "noclassdeffounderror" error. When I check the content of the jar, it does not contain org/ini4j.
I was able to fix this by going into File -> Project Structure -> Artifacts
If I want to add another dependency, I'll have to do this every time, which is quite tedious (I didn't need to do this on NetBeans). I then tried to use the following plugins (which I used on NetBeans) to have Maven create a jar with dependencies automatically.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<mainClass>main.Main</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>1.7.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
On NetBeans, this automatically adds all dependencies to the jar file, but it doesn't do anything on IntelliJ IDEA. I have no idea what I'm doing anymore; nothing works. How can I make IntelliJ IDEA automatically extract a dependency into the output root?
Dose your intellij use the same version on maven that your Netbeans uses? if it checks fine, try another plugin for making a fat jar such as the folowing:
<build>
<plugins>
<!-- any other plugins -->
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>

Eclipse and Maven - resources in jar

I know this question was asked many times before, but I still can't manage it to work.
What I want to achieve is to create jar which will load resource (packed in jar) in runtime, without broking resource loading while executing application from Eclipse.
My project structure is standard:
src/main/java
src/main/resources
src/test/java
src/test/resources
Code for load image resource:
ClassLoader classLoader = getClass().getClassLoader();
splashImage = ImageIO.read(new File(classLoader.getResource("img/splash.png").getFile()));
It is working fine when starting the App from the Eclipse. However, when I export the runnable jar from the Eclipse, it doesn't works.
Exported jar have /resources/img folder in it's root directory. But when the app starts, an exception is thrown:
Caused by: javax.imageio.IIOException: Can't read input file!
How it is possible to make it work from runnable jar file and when running the App from the Eclipse?
I was also trying to build jar with maven plugins, but with no luck.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.8</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>foo.bar.App</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
You should go the following way for loading your resource:
classLoader.getResourceAsStream("/img/splash.png")
The point is that src/main/resources will automatically being copied to target/class which is the root of your classpath. This will work in Eclipse as well from the packaged jar.
An runnable jar will be created by maven via maven-assembly-plugin like this:
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.5.3</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
[...]
</project>
After you have added this you can create the full runnable jar via:
mvn clean package
This will produce a jar file in target folder which looks like: ´whatever-1.0-SNAPSHOT-jar-with-dependencies.jar´.
What i don't understand is the usage of maven-dependency-plugin in your build?

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