I am making a webapp using maven. The problem is that everytime I do maven update project, the Maven Dependencies library disappears from the deployment assembly to WEB-INF. I have to re-add it manually every time. It is similar to problem 1 in this post: Eclipse + Maven + Dynamic Web Project -> Maven overwrites Deployment Assembly
His solution was to update eclipse, but I am already on newest version (mars) and I have all maven plugins installed properly. I know this because I have another web application built using maven that working completely fine without this issue. I've looked through a bunch of settings and the two look completely identical, so I cannot figure out why. Is there some place where I can set so the Maven Dependencies are added automatically to the deployment assembly even after maven update project?
I've been coding Java in Eclipse for awhile without needing to specify dependencies. Now that I learned how Maven does it, I'm wondering: how did Eclipse build projects on its own? How did Eclipse figure out which versions of imports, and which dependencies of dependencies, are needed to make everything work?
Finally, what are the advantages and disadvantages of building a project in Eclipse by starting with New->Other->Maven Project instead of New->Java Project?
To the first question: Eclipse doesn't add any dependency in a standard Java project. You have to manually add to the Build Path all needed JARs, otherwise you'll have compilation errors.
To the second question: if you create a standard Java project Maven is not used, even if you create a pom.xml file in the root of the project. You can always convert a standard Java project in a Maven project (see Convert Existing Eclipse Project to Maven Project).
Your dependencies has always to be in the classpath
When you start a project with Maven, Eclipse will automatically add the Maven repository to the classpath.
When you start a Java project you have to link your library manually in Eclipse and the version of the library is the one you've downloaded.
You can see the difference in your project's Properties > Java Build Path > Libraries
I am trying to use Maven and JDeveloper for a week now and I'm always get stuck with the same problem. I can download and install the extensions and create new Maven projects. When I package or compile them I can see that the sources are being downloaded and added to my local repository but they are not added in my .jar and I cannot use them in my project unless I add them as lib manually in my project.
If I try to add the folder (where the downloaded jars are) as lib folder to project they are only added as jar and I cannot use them.
Is there another way to update my dependencies from JDeveloper? How can I integrate them properly to my project so I can use them? Is there a newer Hands-On maybe solving my problems? What am I doing wrong? Is there a template project to download maybe? I hope I could explain my problem good enough...
I am using play 1.2.4 to create a web app. It works together with some other applications which are maven projects: they are compiled and resolved (dependencies) with maven.
Now I need to modify my play app so it can also be compiled and started with maven.
Therefore I download maven (3.0.4), installed the maven modul and did everything according to https://github.com/wangyizhuo/play-maven and http://www.playframework.org/modules/maven-head/home
I manage to automatically create a pom file in my project. The problem is that the jars from the play framework are not copied into the lib-folder and when I try to execute mvn package they are missing.
Is there a way to get the maven module to work properly? If not, is there another possibility to compile and start the project from maven (i.e. intermediate ant-file that can be executed by maven?)
Many thanks in advance!
This explains it pretty well. I havnt looked at the module you are refering too, but this shows you how you can create tasks and inculde directories in your build.
Do you need to use maven to build/run it? If not it looks like there is a community contributed extension that allows you to use maven from within play.
I am updating an existing project from GWT 1.5.2 to GWT 2.0.0. We use maven 2 to manage our dependencies and do all of our development in Eclipse 3.5.
Because we use maven to manage our dependencies, I do not have all of those jars in the war\web-inf\lib directory as GWT specifies. Instead, they are in the maven repository, just where maven likes them. I have the project set up so that maven can successfully build and launch in either dev or web mode and the application runs correctly.
The problem is that when I launch from Eclipse, I get a java.lang.NoClassDefFoundError. If I manually copy of my dependencies into war\web-inf\lib before launching, everything runs fine, but that doesn't lend itself to a long-term solution. First, if I check all of those jars into our version control, that will subvert much of the value we get from maven. As annoying as maven can be, ditching it is not the answer. Second, having developers manually copy them over every time they want to debug something is ridiculous.
So can I get Eclipse to copy the dependencies into war\web-inf\lib before launching? Is there an alternate solution that I'm missing?
Thanks,
Tony
Running the gwt:eclipse goal will copy the maven dependencies into war/WEB-INF/lib. See the Eclipse Configuration section of the Eclipse IDE Integration documentation of the Maven GWT plugin for more details. Also have a look at this answer about Maven GWT 2.0 and Eclipse.
You should install the m2eclipse plugin and use that to build your project within eclipse. This will invoke maven as an external tool from within eclipse.
Your maven project artifact type should be set to war, which will let maven discover the dependencies and bundle them.
See these links:
force Maven2 to copy dependencies into target/lib
http://maven.apache.org/plugins/maven-war-plugin/
http://maven.apache.org/plugins/maven-war-plugin/examples/rapid-testing-jetty6-plugin.html
a maven aware IDE (idea, eclipse, netbeans) should do this packaging automatically. maybe you:
forgot to enable maven import inside IDE?
did not add these dependencies to the pom.xml (so they aren't included in the 'mvn package' phase)
added wrong scope to dependency declaration (e.g. scope 'provided' or 'tested'), so they are ignored for runtime
If you have the packaging method in your pom.xml set to war it should copy runtime depdencies into target/war/WEB-INF/lib.
Or is your project to build something larger like an ear? If so you should probably split your pom.xml into multi-project format.
As for Eclipse, I'm not terribly familiar with it so I can't really help you there. Are you (or can you) run a maven target (like "install") when you do a run or debug?
This is not supposed to be a problem. If you are using Eclipse+WTP then WTP lets you declare jars listed under 'J2EE module dependency' in the project's properties. Those jars are automatically published to tomcat (see note at the end of this comment)
You need to declare an M2_REPO variable in your eclipse environment (search eclipse help for 'classpath variables'), it should point to your local maven repository, and just add external jars from there to your project and mark them as 'J2EE dependencies'.
I did that with tons of projects, Maven and Eclipse live side-by-side :) (without m2eclipse)
A second option is to try to integrate Eclipse and Maven with m2eclipse plugin, as crowne mentioned, but I found this unnecessary.
There is a third option, if you don't use WTP (but you should). Assuming that you use tomcat, then you can copy those jars to $(tomcat.home)/common/lib. If you can do it just for your private instance of tomcat (on each developer's machine) then you are good to go.
This is supposed to be a low-impact solution that will get those jars into the classpath at runtime, but it doesn't scale well.
note: unfortunately the classpath of Eclipse web projects can be confusing. When you add jars to the regular build path of the project, they are not deployed (copied over) to tomcat. To solve this, WTP defines a special library called Webapp Library - this library contains all the jars in the project's WEB-INF/lib folder, as well as all the external jars that are marked as J2EE Module Dependencies. All those jars find their way appropriately to WEB-INF/lib when published to tomcat.
Quite simple:
1. Create a "lib" folder under your project like this:
"\src\main\webapp\WEB-INF\lib"
2. Copy needed "jars" etc that you want included inside your WAR bundle folder.
3. Invoke your maven build as you normally do. I use "mvn install", which creates builds the war file.
If you examine the WAR file, your jars that you included in step-1 and step-2 will be there.
Cheers.