I had a dependency declared as followed:
<dependency>
<groupId>org.jboss.spec</groupId>
<artifactId>jboss-javaee-6.0</artifactId>
<version>${version.jboss.javaee6}</version>
<type>pom</type>
</dependency>
When I change the scope to provided I get compilation errors such as EJB cannot be resolved to a type. I didn't understand, the documentation says that dependencies declared as provided are still used at compile time, and discarded only at deploy time.
So can someone help me understand these compile errors?
<dependency>
<groupId>org.jboss.spec</groupId>
<artifactId>jboss-javaee-6.0</artifactId>
<version>${version.jboss.javaee6}</version>
<type>pom</type>
<scope>provided</scope>
</dependency>
I think the problem is related to the type that you have mentioned in the dependency of that artifact.
Till now whatever I have played with Maven I cannot think of any case when one would need to add pom type dependency. Generally pom type packaging is used for parent module in a project (specify common project configuration like plugin versions, common dependencies, like log4j for example, repositories, properties etc.) and for utility package module (the one that assembles the project and does some other necessary things).
So, as a suggestion remove the type tag from the dependency until you need it for any specific purpose, let it be default i.e jar.
Related
If I have the following two dependencies in the same pom.xml file:
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
</dependency>
And I'd like to remove the redundancy. So should I delete the one with scope as runtime because it's included in the other dependency?
Also I'd be happy to understand why one would specify a dependency with scope of runtime.
From Introduction to the Dependency Mechanism - Dependency Scope:
compile
This is the default scope, used if none is specified. Compile dependencies are available in all classpaths of a project. Furthermore, those dependencies are propagated to dependent projects.
(...)
runtime
This scope indicates that the dependency is not required for compilation, but is for execution. It is in the runtime and test classpaths, but not the compile classpath.
So if you have a compile dependency, runtime is already included and therefore superfluous.
As an example for when to use runtime, take the SLF4J logging API: you compile your sources against slf4j-api.jar (compile dependency), but not the actual implementation, which is distributed separately (and there are several to choose from). However, when packaging your application or running unit tests, Maven should still include an implementation jar, e.g. slf4j-simple.jar (runtime dependency), because otherwise nothing will be logged.
I changed some existing projects from ant to maven projects.
So far so good.
All projects do have the same groupId.
Theres a project with name "ServerBase" and artifactId "server-base".
Within this project theres an abstract class "BaseService" which defines a logger via:
import org.jboss.logging.Logger;
[...]
protected Logger log = Logger.getLogger(this.getClass());
Theres another project with name "Server" and artifactId "server".
Within this project theres a class ConfigurationDAOImpl extending the BaseService-Class above.
Within ConfigurationDAOImpl the logger log is used for creating some outputs.
Within the "Server"'s POM file I have declared:
<dependency>
<groupId>com.tcom.amadeus</groupId>
<artifactId>server-base</artifactId>
<version>${project.version}</version>
</dependency>
Under BuildPath the dependency is shown very nice under MavenDependencies. I removed the old dirct/natural/ant-dependency from build path before.
If I remove it I am getting very much errors about missing classes etc.
But although I do have this dependency I am getting the followin error in eclipse (under tab markers):
The type org.apache.commons.logging.Log cannot be resolved. It is indirectly referenced from required .class files
Resource: ConfigurationDAPImpl.java
Path: /Server/src/main/...
Location: Line 24
Type: Java Problem
I tried removing the dependency and add it again but without any luck.
Both projects do refer to JAVA 1.8.
Both projects have been build with targets clean an package multiple times.
Both projects have been updated by Righclick or pressing F5.
I am using Eclipse Version: Neon.1a Release (4.6.1)
I am using apache-maven-3.3.9
I am using m2e Plugin.
Any further help would be grateful.
Thanks in advance.
There are two ways to 'solve' this:
1)
explicitly add the required dependency within the server-projects pom-file:
<dependency>
<groupId>org.jboss.logging</groupId>
<artifactId>jboss-logging</artifactId>
</dependency>
2)
change the scop of the required dependency within the server-base-projects pom file from up to now 'provide' to 'compile' or erase the scope tag at all such that the default scope is used by maven (which I guess is 'compile')
old:
<dependency>
<groupId>org.jboss.logging</groupId>
<artifactId>jboss-logging</artifactId>
<scope>provided</scope>
</dependency>
new:
<dependency>
<groupId>org.jboss.logging</groupId>
<artifactId>jboss-logging</artifactId>
<scope></scope>
</dependency>
or:
<dependency>
<groupId>org.jboss.logging</groupId>
<artifactId>jboss-logging</artifactId>
</dependency>
Some background to this from documentation:
http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Transitive_Dependencies
provided This is much like compile, but indicates you expect the JDK or a container to provide the dependency at runtime. For example,
when building a web application for the Java Enterprise Edition, you
would set the dependency on the Servlet API and related Java EE APIs
to scope provided because the web container provides those classes.
This scope is only available on the compilation and test classpath,
and is not transitive.
Thanks all.
It looks like apache logging library is not brought transitively from your server-base project. Check if in project server under MavenDependencies you see commons-logging (apache logging) jar. If not, then add this as your maven dependency in server-base project.
Repeat the above for all jars that server-base depends on.
I'm having trouble correctly importing a library into a project that I'm running. I have added the library as a dependency in the .pom, refreshed the pom, run mvn clean install, and I have set auto-import up so that the project gets updated correctly, but the project does not get added as an External Library, and I can't use it in my project. I get no errors. What am I doing wrong?
Here is the relevant part of my pom
..properties
<crowd.version>2.5.0</crowd.version>
.. end properties
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.atlassian.crowd</groupId>
<artifactId>crowd-integration-springsecurity</artifactId>
<version>${crowd.version}</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</dependencyManagement>
Here is the question I was following to debug my error:
Import Maven dependencies in IntelliJ IDEA
I think you missed the point of dependency management; read more in official docs. This is a feature that you can centralize common dependency information that is then shared been different projects. All by itself, this definioition will not import the dependency.
What you probably want is just a plain dependency: drop the dependencyManagement tags, and move you dependency into the correct block in the pom.
My project is a fairly large project consisting of many maven modules (but not microservices). I was trying to do Moving from spring to spring-bom on WAS but seems lot of clashes in versions. So for example one of my modules is using commons-collectionsversion 2.6.0 and my current project is using 3.2.2. I want the same jar to be used across. Since its more of a migration project I cannot do changes in container or repository changes at this time. I should only make sure that all the version are compatible with each other. My plan :
I want to include a dependency which is with in some other dependency
into the current pom as a dependency.
Also I want other jars in this pom (which exists as a dependency) to included the dependency
Is there anyway to do it?
I didn't completely understand your question, but the can help you to define a cross-module dependency version, as long as you place it in the parent-pom file.
<dependencyManagement>
<dependency>
<groupId>com.group</groupId>
<artifactId>project-1</artifactId>
<version>1.0.0</version>
</dependency>
</dependencyManagement>
and then define the dependency in the relevant module without providing it a version (it will be inherited from the parent-pom's <dependencyManagment> tag:
<dependencies>
<dependency>
<groupId>com.group</groupId>
<artifactId>project-1</artifactId>
</dependency>
</dependencies>
I thought that the order of Maven dependencies doesn't matter before and regard this as a pro of it. And this is my old pom.xml's dependencies:
<dependencies>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<version>2.19</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.1.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.ext</groupId>
<artifactId>jersey-spring3</artifactId>
<version>2.19</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
<version>2.19</version>
</dependency>
</dependencies>
It works well, and today I wanna move spring dependency to the bottom so that those jersey related can be together. However then I can no longer make it working, my Jetty complains:
[ERROR] Failed to execute goal org.eclipse.jetty:jetty-maven-plugin:9.3.0.M1:run (default-cli) on project mtest: Execution default-cli of goal org.eclipse.jetty:jetty-maven-plugin:9.3.0.M1:run failed: A required class was missing while executing org.eclipse.jetty:jetty-maven-plugin:9.3.0.M1:run: org/apache/commons/logging/LogFactory
That is really confusing, so do I have to concern about dependencies order? How do I know the correct order?
The order of dependencies does matter because of how Maven resolves transitive dependencies, starting with version 2.0.9. Excerpt from the documentation:
(...) this determines what version of a dependency will be used when multiple versions of an artifact are encountered. (...) You can always guarantee a version by declaring it explicitly in your project's POM. (...) since Maven 2.0.9 it's the order in the declaration that counts: the first declaration wins.
To expand upon the other answer (which states that the declaration order affects Maven's dependency mediation for transitive dependencies), there are a few tools you can use:
mvn dependency:tree [-Dscope=[runtime|test]] will show you what dependencies will be available for the selected scope. See here for details
mvn dependency:build-classpath gives you order in which dependencies are available on your classpath (if two or more classpath entries have the same class, the earlier one wins). See here for details
I don't know much about your situation, but it's often the case that you wind up with the wrong version of 1 or more jars at compile/runtime. Declaring your own version of the library in question or locking down the version with <dependencyManagement> are options here.
Now to answer your other question - how do you know what the right order is when declaring dependencies?
My suggestion - the right declaration order is the one that gets you the versions of the dependencies you want, in the order you want them in. Use the tools above to check your dependencies, and tweak the declared order if necessary.
Note that most jars contain disjointedly-named classes, so the exact order in which jars appear on your classpath is usually not that important. The only exception I've noticed is some jars in SLF4J which intentionally shadow classes from the other logger libraries it's intended to replace.