We have a multi module maven project where previously we load our classes from a jar dependency as below
<plugin>
<groupId>xxxx<groupId>
<artifactId>xxx<artificatId>
<version>xxx</version>
<dependencies>
<dependency>
<groupId>yyyy<groupId>
<artifactId>yyyy<artificatId>
<version>yyy</version>
</dependency>
.
.
</dependencies>
</plugin>
Now due to business requirement,
I want remove dependency (yyyy) and use that dependency code as part
of project/src folder
No more dependency used -- business condition
3.. Plugin XXX has to load classes from project/target of project.
Issue here is when plugin xxx is running it is looking for classes which are defined as dependency but not from project target folder.
Please suggest how to proceed ?
Is there a way to have a single Spring Boot project be packagable into both JAR and WAR without changing the pom.xml or the application source?
I've read Converting a Spring Boot JAR Application to a WAR, but it converts the project to WAR and it loses the ability to be packaged as JAR.
I don't expect mvn package to do both. What I want is something like mvn i-want-a-jar and it would package the project as JAR. Or I could run mvn i-want-a-war and it would package the project as WAR.
Is this possible?
I managed to do it by adding
<packaging>${packaging.type}</packaging>
to the POM file and then setting different profiles for JAR and WAR:
<profiles>
<profile>
<id>jar</id>
<properties>
<packaging.type>jar</packaging.type>
</properties>
</profile>
<profile>
<id>war</id>
<properties>
<packaging.type>war</packaging.type>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
</dependencies>
</profile>
</profiles>
Now mvn package -P war produces a WAR and mvn package -P jar produces a JAR.
Another option is to create separate modules for JAR and WAR, but I didn't go that route.
What's wrong with a WAR file that's executable? Isn't that what you really need?
P.S. like
java -jar name.war
We've recently had a similar requirement, where an existing Spring Boot based project that was originally packaged as an executable Jar needed to support Tomcat and WildFly deployments.
Due to some dependencies used in this project (for example WebJars), a simple switch to WAR package wasn't an option since some of those dependencies were required for WildFly (VFS support) but not for other deployment.
The solution was to restructure the project modules in a way that core module contained the actual project but without having Spring Boot’s plugin applied, while several package modules would depend on core module and configure deployment artifact specifics (Boot and other plugins, deployment specific dependencies etc.).
That way project build was able to generate multiple deployment artifacts (Boot's executable JAR, traditional WAR and WildFly specific WAR) in a single build run.
In case anyone finds this useful, the sample project to demonstrate the approach is available on Github. The project can be built by either Gradle or Maven.
I have an osgi-bundle which is created by using the maven-bundle-plugin:
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId>
<configuration>
<instructions>
<Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
</instructions>
</configuration>
</plugin>
The bundle is installed via the maven-sling-plugin.
I have a fasterxml.jackson dependency which exists as an osgi-bundle in my .m2 repo and acts as a dependency in my project.
How can I make maven deploy this dependency as an osgi-bundle as well?
At the moment I have to install it manually in my osgi-container.
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.2.2</version>
</dependency>
EDIT:
Simplification:
How do I make maven realize that an osgi-bundle which I refer to as a dependency in my pom.xml shall be installed in the osgi-container along with the bundles that depend upon it?
You'll probably find its best to package your bundle as part of your application along with the /content, /apps portions of your application in the /apps/myapp/install folder will cause the libraries to be installed as bundles by the jcr installer provider.
There are a couple of ways of automating packaging/deployment of applications using maven described in these articles:
http://www.cognifide.com/blogs/cq/maven-plugin-automating-deployments-of-crx-cq-applications/
http://mkalugin-cq.blogspot.co.uk/2012/11/how-to-use-maven-project-to-create.html
http://labs.sixdimensions.com/blog/dklco/2012-05-03/introducing-cq-deploy-maven-plugin-deploying-cq-projects
http://dev.day.com/docs/en/cq/current/core/how_to/how_to_use_the_vlttool/vlt-mavenplugin.html
Alternatively, you could just use the CRXDE to place the bundles and then CRX Package Manager to test the approach, them move on to automated packaging later.
If you don't want to repackage the two OSGI bundles, you can use the sling maven plugin to install the jackson bundle directly
mvn org.apache.sling:maven-sling-plugin:install-file -Dsling.file=jackson-databind-2.2.2.jar
Created project with Spring, Hibernate & Maven. My question is what is the logic behind plugin versus dependency ?
Both plugins and dependencies are Jar files.
But the difference between them is, most of the work in maven is done using plugins; whereas dependency is just a Jar file which will be added to the classpath while executing the tasks.
For example, you use a compiler-plugin to compile the java files. You can't use compiler-plugin as a dependency since that will only add the plugin to the classpath, and will not trigger any compilation. The Jar files to be added to the classpath while compiling the file, will be specified as a dependency.
Same goes with your scenario. You have to use spring-plugin to execute some spring executables [ I'm not sure what spring-plugins are used for. I'm just taking a guess here ]. But you need dependencies to execute those executables. And Junit is tagged under dependency since it is used by surefire-plugin for executing unit-tests.
So, we can say, plugin is a Jar file which executes the task, and dependency is a Jar which provides the class files to execute the task.
Hope that answers your question!
Maven itself can be described as food processor which has many different units that can be used to accomplish different tasks. Those units are called plugins. For example, to compile your project maven uses maven-compiler-plugin, to run tests - maven-surefire-plugin and so on.
Dependency in terms of maven is a packaged piece of classes that your project depends on. It can be jar, war etc. For example, if you want to be able to write JUnit test, you'll have to use JUnit annotations and classes thus you have to declare that your project depends on JUnit.
Plugins and dependencies are very different things and these are complementary.
What plugins are ?
Plugins perform tasks for a Maven build. These are not packaged in the application.
These are the heart of Maven.
Any task executed by Maven is performed by plugins.
There are two categories of plugins : the build and the reporting plugins :
Build plugins will be executed during the build and they should be configured in the <build/> element from the POM.
Reporting plugins will be executed during the site generation and they should be configured in the <reporting/> element from the POM.
According to the maven goal specified in the command line (for example mvn clean, mvn clean package or mvn site) , a specific lifecyle will be used and a specific set of plugins goals will be executed.
There are three built-in build lifecycles: default, clean and site. The default lifecycle handles your project deployment, the clean lifecycle handles project cleaning, while the site lifecycle handles the creation of your project's site documentation.
A plugin goal may be bound to a specific phase of a specific lifecyle.
For example the maven-compiler-plugin binds by default the compile goal to the lifecycle phase: compile.
Most of maven plugins (both core plugins and third party plugins) favor convention over configuration. So these generally bound a plugin goal to a specific phase to make their usage simpler.
That is neater and less error prone :
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
</plugin>
than :
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
What dependencies are ?
Dependencies are Maven artifacts/components required for the project.
Concretely most of dependencies are jar (that is libraries) but these may also be other kinds of archives : war, ear, test-jar, ejb-client ... or still POM or BOM.
In a pom.xml, dependencies may be specified at multiple places : the <build><dependencies> part , the dependencies management part or still in a plugin declaration ! Indeed some plugins may need to have some dependencies in the classpath during their execution. That is not common but that may happen.
Here is an example from the documentation that shows that plugin and dependency may work together :
For instance, the Maven Antrun Plugin version 1.2 uses Ant version
1.6.5, if you want to use the latest Ant version when running this plugin, you need to add <dependencies> element like the following:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.2</version>
...
<dependencies>
<dependency>
<groupId>org.apache.ant</groupId>
<artifactId>ant</artifactId>
<version>1.7.1</version>
</dependency>
<dependency>
<groupId>org.apache.ant</groupId>
<artifactId>ant-launcher</artifactId>
<version>1.7.1</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
...
</project>
In Maven, dependencies are referenced in a specific format :
groupId:artifactId:packaging:classifier:version.
The classifier (that is optional) and the packaging (JAR by default) are not commonly specified. So the common format in the dependency declaration is rather : groupId:artifactId:version.
Here is an example of dependency declared in the <build><dependencies> part :
<build>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.14.Final</version>
</dependency>
<dependencies>
</build>
Dependency doesn't have a phase binding as plugins to address the "when" question.
But it has a counterpart : the scope.
Indeed declared dependencies are usable by the application at a specific time according to the scope we defined for these.
The scope is a central concept about how a dependency will be visible for the project.
The default scope is compile. That is the most commonly needed scope (convention over configuration again).
The compile scope means that the dependency is available in all classpaths of a project.
The scope defines in which classpaths the dependency should be added.
For example do we need it at compile and runtime, or only for tests compilation and execution ?
For example we previously defined Hibernate as a compile dependency as we need it everywhere : source compilation, test compilation, runtime and so for....
But we don't want that testing libraries may be packaged in the application or referenced in the source code. So we specify the test scope for them :
<build>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>5.1.0</version>
<scope>test</scope>
</dependency>
<dependencies>
</build>
One line answer - basic understanding
Plugin is a tool you use at the execution of your maven build
Dependency means kind of any library which you will use in your code
If you're coming from a front-end background like me, and are familiar with Grunt and npm, think of it like this:
First you would run, say, npm install grunt-contrib-copy --save-dev. This is like maven's <dependency></dependency>. It downloads the files needed to execute a build task.
Then you would configure the task in Gruntfile.js
copy: {
main: {
src: 'src/*',
dest: 'dest/',
},
}
This is like maven's <plugin>/<plugin>. You are telling the build tool what to do with the code downloaded by npm/<dependency></dependency>.
Of course this is not an exact analogy, but close enough to help wrap your head around it.
Plug-ins are used for adding functionalities to Maven itself (like adding eclipse support or SpringBoot support to Maven etc.). Dependencies are needed by your source code to pass any Maven phase (compile or test for example). In case of JUnit since the test code is basically part of your code base and you call JUnit specific commands inside test suites and those commands are not provided by Java SDK therefore JUnit must be present at the time Maven is in the test phase and this is handled by mentioning JUnit as a dependency in your pom.xml file.
In simple words:
Plugins are used to add some additonal features to the software/tools(like Maven). Maven will use the added plugins at the time of building when we use the build command.
Dependecies are used to add some addtional code to your source code, so a dependency will make some extra code (like Classes in Java) in the form of library available for your source code.
Maven at its heart is a plugin execution framework -- as per formal and standard compact definition. To make it more clear, the commands you use like maven-install/clean/compile/build etc for creating/executing jars, which we sometimes manually run too. So, the things which you want to run (or configure or execute) you basically put them in dependency tag of mavens pom and the answer so as to who will run these dependencies (required for environment setup) be the plugins.
javac (compiler) dependency.java (dependency)
A plugin is an extension to Maven, something used to produce your artifact (maven-jar-plugin for an example, is used to, you guess it, make a jar out of your compiled classes and resources).
A dependency is a library that is needed by the application you are building, at compile and/or test and/or runtime time.
I've got a Maven plugin that depends on slf4j for logging. The default behavior is too chatty for my liking but I can't figure out how to add my logback.xml to the plugin's classpath.
<plugin>
<dependencies>
</dependencies>
</plugin>
allows you to add dependencies to the plugin's classpath, but how do you add local (resource) directories?
You have to wrap your logback.xml into a proper Maven artifact (i.e. a jar) and install it to local repository or deploy to your shared repository, or use systemPath in your dependency declaration to point to a jar placed somewhere inside of your project, which is highly not recommended.
The reason for this is reusability of your build. Think how others would be able to reproduce it.
You don't. You must package them up as an artifact and add it as a dependency.