Missing Maven dependencies in Eclipse multi-module project - eclipse

I’m using STS 2.9.1 (build on Eclipse 3.7.2) with m2e plugin bundled with STS (v1.0.200.20111228-1245).
I have a problem regarding missing dependencies in Eclipse project that contains several modules, or maybe I don’t fully understand how it should work.
It’s a maven project.
In my Project > Properties > Java Build Path > Libraries I have “Maven Dependencies” library, but it's empty (and that’s the problem).
The main POM doesn’t have any dependencies, but it has several modules declared in it.
Adding a dependency to module’s POM doesn’t add it to the “Maven Dependencies” library (what was my expectation) and leads to Eclipse showing errors in source files.
Adding a dependency to the main POM adds it to the “MD” lib, but of course I don’t want to add all of my modules’ dependencies to the main POM just to have it in “MD” lib and adding every single dependency to the Build Path doesn’t seem right nor practical.
I’ve tried:
Project > Clean,
Maven > Update dependencies,
Maven > Update project configuration,
Unchecking the checkbox: Project > Properties > Maven > Resolve dependencies from Workspace projects.
None of the above seems to do the trick.
Example:
Simplified project structure:
simple.project
...
sample-module
...
pom.xml
pom.xml
simple.project/pom.xml:
<project ...>
<modelVersion>4.0.0</modelVersion>
<groupId>test</groupId>
<artifactId>simple.project</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>sample-module</module>
</modules>
<dependencies>
<dependency><!-- This dependency is present in "MD" lib. -->
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
simple.project/sample-module/pom.xml:
<project ...>
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>simple.project</artifactId>
<groupId>test</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<groupId>test</groupId>
<artifactId>sample-module</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency><!-- I've expected this dependency also to appear in "MD" lib. -->
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>

It is not supposed to work. A project only imports a dependency from another one if it depends on that project (using dependency) or if it inherits from it (using parent). The module element only represents an aggregation.

The question is from time ago, but I solved this creating a Maven Project and adding Maven Modules: right click on project and "New > Project... > Maven > Maven Module".
After that, no more errors were shown in code.

First thing that I see is that you're defining dependencies in a pom parent. There I would expect to see a <dependencyManagement> (see here the doc) structure. In this way the submodules will inherit properly those common dependencies.
Aside from that lets start for the most simple test. Try to compile your project from the maven utility in the command line. If it works then you have a problem in your Eclipse configuration, otherwise the problem is in the way you have defined your project.
If your project compiles properly from the command line, lets see what else can be happening.
The fact that the Maven Dependencies Library is empty means that the Eclipse Maven plugin is not resolving properly your poms. I had quite bad experiences with the embedded STS maven plugin. Try to downgrade it to the m2e 0.10 version. You only need to open the STS DashBoard / Find Updates / Install m2e 0.10
I hope some of these tips can help you.

Related

MILO OPC-UA Download with Maven

I tried to use the milo opc-ua Implementation. At first I download the source with Eclipse/Maven to my local working directory.
File -> Import -> "Checkout Maven Projects"
The Download works fine for me. After this, I tried to update the project files.
Right-Click -> Update Maven Project
The "build-tools" work well for me, everything is done without any errors. But when I try this with the other "folders" (client-examples, ...) I get the following error:
Plugin execution not covered by lifecycle configuration: org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check (execution: validate, phase: validate).
The following code shows the pom-file of the client-examples:
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<parent>
<groupId>org.eclipse.milo</groupId>
<artifactId>milo-examples</artifactId>
<version>0.1.0-SNAPSHOT</version>
</parent>
<artifactId>client-examples</artifactId>
<dependencies>
<dependency>
<groupId>org.eclipse.milo</groupId>
<artifactId>sdk-client</artifactId>
<version>0.1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.eclipse.milo</groupId>
<artifactId>server-examples</artifactId>
<version>0.1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.7</version>
</dependency>
</dependencies>
The pom.entries, shown in https://github.com/eclipse/milo, are in the file. I also checked this for the other sources. But whats going wrong?
I'm using eclipse-neon and maven2eclipse.
Thanks for helping,
Andreas
The errors says that the M2Eclipse plugin has no idea how to map the execution of checkstyle into some build step for the IDE. M2Eclipse tries to set up your local IDE project to replicate the behavior of the Maven build.
By default M2Eclipse is missing the support for the checkstyle Maven plugin. Therefore you get this error. There are two ways to handle this:
You can simply make Eclipse ignore those errors
You can install the checkstyle plugin for Eclipse and have checkstyle run the same way the maven build does it, getting all validation information right into your IDE.
In order to install checkstyle do the following:
Locate the location where the error is reported in Eclipse, issue the "Quick fix" command (normally Ctrl-1)
Select "Discover new m2e connectors":
Review the dialog and press "Finish":
Wait and let Eclipse restart
That should be it.

eclipse maven external jars unable to compile

Maven compilation failes even after adding the external jars to eclipse. My Eclipse codes are okay with external jars, however when I compile Maven complains package blah blah not found, and I have almost 50 external packages.
I will use the mvn dependency to add the jars later.
However It should work, but not luck.
Any troubleshooting/suggestion please.
I think you can not get away with Maven Project without having <dependencies> tag in your pom.xml (Whether you run it from eclipse or from command-line) . That too for the project which is dependent on classes that are coming from 50 external jars.
If you don't want maven to look for these jars, you have to add below entry in pom.xml with system scope:
<dependencies>
<dependency>
<groupId>selenium-server-standalone</groupId>
<artifactId>selenium-server-standalone</artifactId>
<version>2.46.0</version>
<scope>system</scope>
<systemPath>${project.basedir}/lib/selenium-server-standalone-2.46.0.jar</systemPath>
</dependency>
</dependencies>
With this, groupID & artifactID are meaningless. You can write such 50 <dependency> tags for referring your 50 external jars.

Maven: Jar in Referenced Libraries despite not showing in effective POM

Before importing my Maven project, I build it using the following: mvn clean install
I then create the necessary Eclipse files as follows: mvn -Dwtpversion=2.0 eclipse:eclipse
I notice that my Referenced Libraries in Eclipse contains this jar: validation-api-1.0.0.GA.jar
However, when I view the effective POM in Eclipse no such jar appears. Therefore, I am wondering how this jar gets added to my Eclipse classpath?
I require this jar for #Valid annotation I am using and I need Maven to be aware of it. If I build my classpath files using Maven then how come Maven is not aware of it?
Thanks
Check the Dependency hierarchy-tab in your pom (in Eclipse), maybe the jar is a dependency of some other jar you use.
In this case, the reference was in the project's Java Build Path, and was probably added when the project was created because of the -Dwtpversion=2.0 -parameter.
Maven also adds to your class path the sub-dependencies of your main dependencies (which are those specifically declared by you in the pom.xml). Do a
mvn dependency:tree -Dverbose
To see what other dependencies are pulled in with a specific pom-declared dependency.
Also, if you only wanna see the subdependencies of a certain dependency, called x.y.z you can do:
mvn dependency:tree -Dverbose -Dincludes=x.y.z
(where x.y is the groupId and z is the artefactId)
One of your project dependencies probably has a dependency for this jar file. Check the graphical dependency graph or just search for that, find out your project dependency that is dependent on this and exclude this dependency, if possible, by using maven's 'exclude' tags.
You can use maven dependency exclusions, as below:
<project>
...
<dependencies>
<dependency>
<groupId>sample.ProjectA</groupId>
<artifactId>Project-A</artifactId>
<version>1.0</version>
<scope>compile</scope>
<exclusions>
<exclusion> <!-- declare the exclusion here -->
<groupId>sample.ProjectB</groupId>
<artifactId>Project-B</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
</project>
Source: Maven - Dependency Exclusions
I have encountered the same problem. And after some research I realized that transitive dependencies of your parent pom may not show up in Effective POM, but would be present in Reference libraries.
The whole confusion raised because when I ran the following command
mvn dependency:tree -Dincludes=X (where X is the group-id of the jar I was looking for)
It did no mention of parent pom, instead it referred to dependency in parent pom which brings X to the table. (Which make sense because we inherit from parent pom).

Maven dependency and eclipse classpath

I tried to search for existing questions but cant find any - feels like my question is quite simple but probably because it's quite specific I cant find the answers on Stackoverflow / Google.
Anyways - I have few projects with Maven that are depend on each other. In certain cases I want the dependency to be on the JAR rather than a project dependency (ie. I want the dependency to be part of the "Libraries" in Eclipse rather than "Projects" in the Build Path).
Your help is greatly appreciated! Thanks
To get the referenced projects in the same workspace as jar files instead of the projects, we could use the VM parameter -Declipse.useProjectReferences=false or add it in the pom file.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<useProjectReferences>false</useProjectReferences>
</configuration>
</plugin>
See this URL for more info.
In your project properties in Eclipse, select Maven. There is a checkbox, 'Resolve dependencies from workspace projects'. If this is checked, then the Eclipse projects are used. Otherwise the jars are used as with other maven dependencies, assuming that you've got the dependencies in your pom.xml as normal.
EDIT: If your project is not a maven project, then you'll have to create the jar outside Eclipse and add it as a jar or external jar as normal. If the project is a maven project, then the above will work.
Say Client-Project depends on Services-Project. If Services-Project generates a JAR. In the Client-Project POM you would express a dependency on this JAR. It would be something like:
<dependency>
<groupId>group.id.of.services.project.goes.here</groupId>
<artifactId>artifact.id.of.services.project.goes.here</artifactId>
<version>version.number.of.services.jar</version>
</dependency>
If services project generates a JAR called com.mycompany.services-1.3.jar, the dependency would be:
<dependency>
<groupId>com.mycompany</groupId>
<artifactId>services</artifactId>
<version>1.3</version>
</dependency>

Eclipse Maven runtime dependencies and profiles

Im trying to understand maven profiles and have run into the following issue.
This is my simplified example, I have two maven projects, project A and Project B.
project A has a compile time maven dependency on project B.
project B includes a runtime dependency (lets say to project C) when the maven profile "TEST" is active.
so the problem is the class path generated when I run project A. it doesn't have project C in it, even though the TEST profile is active for project A.
this is using eclipse Helios service release 1, Maven Integration for Eclipse plugin vrs 0.10.2.20100623-1649
any ideas?
I'm not sure that profiles are the best way to handle with TEST.
The use of profile to change dependecies will change the POM of the generated project.
If you install Project B with TEST activated, the runtime dependency will be added. (Whatever project A profile).
Optional dependencies are not added by transitivity. You need to add the dependency in project A.
I just tested this in Eclipse using m2eclipse 0.12.x. The second project pom.xml look like this:
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>org.test</groupId>
<artifactId>test2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<profiles>
<profile>
<id>TEST</id>
<dependencies>
<dependency>
<groupId>org.test</groupId>
<artifactId>test1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</profile>
</profiles>
</project>
Then I set profile TEST as an active on Maven panel in the project properties dialog and made sure dependency resolution from Workspace is enabled there.
After that you can run any classes from test2 project's src/main/java and generated classpath looks like this:
C:\Dev\Java1.6\bin\javaw.exe -Dfile.encoding=Cp1252
-classpath C:\Dev\Workspace\test2\target\classes;C:\Dev\Workspace\test1\target\classes org.test2.Test2
Note, that dependencies with runtime scope only works for "Java Application" launch configuration type in Eclipse, but not for "JUnit" launch configuration, which uses different classpath resolver provided by m2eclipse's JDT integration.
It seems dependencies that are within profiles of dependent projects (transitive) dont give there runtime dependencies to the person who depends on them, This seems strange.
A work around was to add the profiles (containing the dependencies) to a parent then the children inherit the dependencies.
i.e. introduce a parent to A, I could have put them directly in A as YMomb kindly suggested. but its the inheritance aspect of this issue I needed to resolve as I have lots of projects As.