I have one single external installation of Maven 3.0.4 and two Eclipses (Juno and Indigo) referring it in their m2e settings.
Also I have one single user setting file which describes one single local repository. Both Eclipses refer it.
I have a problems with Maven which can be suspected as conflict between Eclipses.
For example, one of Eclipses (say Indigo) can be blind concerning some global repository (say central). This means that it's subnodes in "Maven Repositories" view of eclipse are empty
Updating/Rebuilding index does not help and probably does nothing since ends very fast.
Reloading settings also does not help.
The question is: is it possible to use one single maven with several Eclipses? Is it possible that principal multiuser system does not support multiusing?
Where the data can be corrupted?
You would be better of ignoring the Eclipse specific installs of Maven.
I have found that relying on pre-installed software on Eclipse, leads to problems for the following reasons.
You will never know exactly what version of maven they have installed and why (finding out is harder than installing yourself)
If it won't run in the IDE, what chance will your build server have (and you will meet those problems in Jenkins or your CI server when it comes to release time)
It is very easy to install Maven yourself and run it from the commandline and less problematic.
http://maven.apache.org/download.cgi
If there is a team of developers using maven think about hosting it yourself on a nexus server.
Related
I'm kinda newbie to Maven and Continuous Integration, so excuse my trivial questions below
In our project we intend to introduce the Continuous Integration through performing automated daily builds on our development integration server using Maven and hudson
on our projects we used to check-in the all the jars (internal, commercial & 3rd party) to SCM under one separate project and force the web project to depend on that project so that the project can compile in eclipse then exporting an EAR
my question is, how will each developer locally on his machine compile the project now ?, should we remove the jars project at all from scm ?
If yes : does this mean that each developer must refer to the enterprise's maven repository from within eclipse so that the project can compile ? and in that case there will be extreme NW overhead ??
If No : there might be a conflict between jars on scm and those in maven repository
another question that is related to the above one, will each developer have his own maven local repository on his machine ?
final question, shall each developer compile the code using maven (through M2Eclipse) or using eclipse compiler as normal ?
thanks :)
The way we do, and I believe is quite common, is
We have our own installation of a repository manager, for example Nexus, installed at some machine in the intranet, available for all developers to use
Jars would not be in the SCM, but stored in the Nexus or equivalent. Common arrangement is to have there one repo for external dependencies, one for internal snapshot builds and one for internal release builds (per project). We have defined maven central repository as well as the internal repositories in Maven configuration, storing the artifacts in the relevant internal repositories (external, internal-release or internal-snapshot) and picking them up from there, but having central repo as a backup for standard plugins.
Repository references (definitions, urls) are either in Maven settings file or then in the pom.xml. Individual developer should not need to do anything, he/she just uses these files. pom.xml would be in the SCM, settings file could be there or not.
Maven uses also local cache when it downloads the files, so they are downloaded only once per version/machine, which should keep the NW overhead tolerable. Intranet repo is there also partly to reduce external network overhead.
Maven release plugin is often used to handle internal-snapshot and internal-release repository updates
Each developer has a local repository cache in his machine. This is a standard Maven feature. Eclipse can refer to these same files.
Code can be compiled with the help of eclipse-maven plugin (of which M2E is the most common), using Maven on the command line or then using Maven to generate regular Eclipse project files and then normally with Eclipse. We use command line and M2E+Eclipse both for this.
SCM would be for source code, repositories for binaries (including .jars)
You configure all dependencies in the pom.xml for each project. Maven then downloads all needed jars from your enterprise repository. You don't need your SCM project any more and i would remove it.
I don't think there is much network overhead, because Maven only downloads the jars the first time they are needed. After that, they are in the local repository (which every developer has on his machine), and only updates will be downloaded after the first time.
If you use M2Eclipse, then the standard Eclipse compiler will be extended with Maven builders, so you can use all Eclipse compile features.
I'm having this problem for a while now. I tried so many things that failed that I had to switch to netbeans in order to be able to develop. But netbeans lacks some important features, so I really need this to work in eclipse.
From scratch:
I have a "parent" maven project with several modules in our svn repo. 2 of the modules are web projects that I need to deploy in a tomcat server. These web projects have several dependencies, among them are the other modules of the parent maven project.
I had this configuration running with eclipse ganymede, but 3 weeks ago I started to get ClassNotFoundExceptions while starting the server, I have no clue why this started happening.
Since then I've tried to get new Eclipse (Java EE) packages, but no matter how I do it, this is what happens:
I get eclipse with maven+svn running and add my tomcat installation to eclipse's server list.
I check out the parent project, this includes the modules. Eclipse gives me a whole list of projects.
The crap starts: I cannot add the 2 web projects to the tomcat, it tells me no projects can be added (meaning "you dont have any web projects!"). Also, I cannot choose "Run as -> Run on Server" on Servlet classes ("Selection did not contain any resources that can run on a server"), even though they clearly extend HttpServlet. Since I spent way too many hours into this, I found out how to deal with this: Convert the project into a "Faceted Project" in the project's properties.
Now I can add both projects to the tomcat server
When starting the server, i get
FATAL: Error loading WebappClassLoader
context: /BEWeb
delegate: false
repositories:
/WEB-INF/classes/
----------> Parent Classloader:
org.apache.catalina.loader.StandardClassLoader#55ae3b4d
de.comp.utils.servlet.SInvokerServlet
This class is in one of the modules that are listed as a dependency
WEB-INF/lib of the deployed project ist empty. No libs at all, maven and/or eclipse doesn't do what it did 3 weeks ago.
I tried messing around with the eclipse files in .settings and also with .project and .classpath, but nothing useful turned out.
Can someone point me in the right direction? I'll do everything from scratch if you need me to, it would not make a difference as I did this a lot of times already (with different versions of eclipse, maven, tomcat, ...)
If you need me to post any files, I'll be happy to comply.
Since this kept me awake at nights for quite some time now, I'll put a bounty on this one.
thx so far.
================================
EDIT in order to answer the upcoming questions
Just to check: building your projects from the command line and deploying them by hand does work, right?
Yes, mvn package works fine, copying that .war file to tomcat results in a working application, also the war file contains all dependencies.
When you say "get new Eclipse (Java EE) packages", do you mean you are now using Eclipse Indigo (3.7)?
Yes. But I had the same problems with 3.5, the eclipse versions didn't show any difference in their behavior.
When you say "I get eclipse with maven+svn running", are you using m2eclipse or have you generated eclipse configuration using maven eclipse plugin?
I have m2e installed and checked out the projects from svn using "Right click -> Checkout as Maven Project". There are no eclipse-specific files in the repository though, it seems they are being generated upon checkout.
When I use mvn eclipse:eclipse, then close+reopen the projects, I cannot add them to the tomcat server ("There are no resources that can be added or removed from the server"), meaning that eclipse does not recognize them as web projects.
First of all: do not use the maven-eclipse-plugin together with m2e/m2eclipse, the two are not compatible. m2e should be able to import your Maven projects and set them up as Eclipse expects.
Did you install the WTP add-on for m2e? This blog post may be worth reading.
If any of your pom.xml files invokes any specific plugin (e.g. for code generation) you may need a corresponding m2e add-on. This wiki post may give you an idea of why.
Another attempt you might consider is setting up a Helios based environment. Check that all the plugins you might need are still available, though.
Bootstrapping Eclipse on new machines is such a time consuming process, you wind up asking yourself whether you really need each plugin. But there all handy, and help develop consistent habits.
Eclipse bootstrapping problems include:
Explaining / documenting what needs to happen
The actual time pasting in the right URLs and downloading
Version compatibility and dependencies
Eclipse likes to restart after each one
The changeover to the Eclipse Marketplace means that some plugins and instructions you find on the web tend to be inconsistent, depending on when they were written.
The Licenses... over and over and over... yes, yes, yes... I understand that the person installing needs to be aware of it, and have a chance to review them, but there's got to be a better way.
It'd be nice to have "patch file" (either binary or meta) that spells out what I want to add on top of stock Eclipse installation. I'd really like to find (or create) a 1 or 2 step process that sets up Eclipse, plus a favorite batch of plugins:
subclipse
m2eclipse
jetty support like runjettyrun
android sdk and plugin (or at least just the plugin)
aspectj
Web Objects / WOLiops
python, other langs
JVM Monitor, maybe EclEmma
probably a git plugin pretty soon.
Does command line maven help with any of this? It seems like its repository management would fit at least part of the functionality.
On a machine with an Eclipse installation matching your needs use File -> Export -> Install -> Installed software items to file. Import the generated file using the same menu on all other machines.
As Scott says, a good approach is to simply package a fully prepared Eclipse installation once all the plugins you need are installed. The downside is that you have to update most plugins afterwards.
Another option is to use Yoxos. With it, you can create a profile and configure it with all the plugins you need (and apparently Yoxos can do more than that).
Finally, this page might interest you concerning the configuration side of things.
Solution 1 is too search for more advanced Eclipse distributions.
For example, STS (Spring Tool Suite) comes with
AspectJ
EGit
m2e
(and of course) Spring IDE
One small trick can be done with m2e-android - Android Configurator for M2E Maven Integration. If installing it on clean Eclipse, it will also automatically resolve to install :
m2e
Android Developer Tools (ADT)
How do you manage your Eclipse installation, i.e. the basic installation, plug-ins and workspace settings with regard to consistent updates (including major ones, 3.5 => 3.6) and usage on two or more computers (desktop + notebook).
My current setup is to basically managing the installation on several installations in parallel, i.e. manually add new plug-ins I installed on one to the other, and when I haven't used one in a long time to copy the whole directory from one location to the other.
For updates I usually run it about once a month to get the latest versions, major updates I do manually by downloading the basic distribution and re-installing all the plug-ins in the matching version for the new major Eclipse version.
However, this approach has some drawbacks:
time intensive
update inconsistencies (Update sites change location, update doesn't work because of some version inconsistency between plug-ins that requires a lot of manual fixing, etc) (this has gotten better with 3.5 but still bugs me)
no "global" update site, I manually have to manage several locations
I tried alternatives like Yoxos for configuration management but there plug-ins were missing and / or not that well tested together as I expected.
I took a look at Idea as an IDE, the one thing I really loved was the update management: centralized and 90% of the functionality I'd be using are provided as a core that is tested and updated as one.
Thus the question: How do you manage your Eclipse installations and deal with updates?
From my experience with other Eclipse users they have at least the same problem with updates, but I haven't heard of a solution yet.
I've heard good things from other developers about Google's Workspace Mechanic.
That's what they use inside Google to manage Eclipse environments across teams.
It was open sourced in May 2010, and you may find more information in the blog post.
Note that the Workspace Mechanic does not yet manage plug-in installations (see discussion thread): it remembers "plugin preferences", but installing the plug-in themselves is not yet supported.
I also met such inconvenience. I always need install similar development tools(such as Mylyn, SVN, CDT, Clearcase) in different eclipse instances on different hosts(Windows, Linux).
Update:
Eclipse has officially offered a feature to help migrating what you have installed since Eclipse Indigo.
And it also supports install existing plug-ins from another instance.
My strategy is as follows:
When a new Eclipse version comes out, I install it fresh and set up a fresh workspace. Then, I install all the minimal plugins I need manually, such as Subversion and M2Eclipse. Also, I export the preferences (e.g. code formatting) to an external file and reimport it in the new Eclipse installation.
I always import existing projects into the workspace. I can use my workspaces (or better, my SVN working copy) from multiple Eclipse versions if necessary.
I only occassionally install additional Eclipse plugins and try to move all other toolchain parts into the build environment (e.g. Hudson with several slaves, automated builds and release scripts, Sonar for code-quality reports etc.)
I try to minimize the complexity of the development setup on my local developer machine.
I only have one installations but I have multiple workspaces.
I synchronize the workspace setting by copying the content of <workspace_dir>/.metadata/.plugins/org.eclipse.core.runtime/.settings directory.
I also use the bookmarks to centralized to save the update-sites relevant for my work. This can act as a global update site. To import/export some bookmarks, go in Preferences -> Install/Update -> Available software sites. When a new Eclipse version comes out (once a year), I only have to install the plugins using the bookmarks.
I am new to maven. The main feature I benefit from, yet, is the automatic dependency management. The standardized directory structure seems also to be nice, but Eclipse has a standard directory structure, too. The directory structure is now independent from Eclipse, but now it is dependent from maven. OK, I see, both programs seem to be quite flexible at this point.
I am not quite sure, if maven is more dedicated to servers or to client systems, e.g. there is a feature / plugin to generate a project website. Doesn't this make most sense on a server system?
How to integrate maven with a version control system (VCS), e.g. SVN? I think of a system where there is a repository and always up-to-date website with download section for development artifacts.
How to integrate maven with Eclipse? I'm now using m2eclipse with WTP integration. Its ok, but it has some behaviors that I don't like, e.g.:
When I generate new Java projects the JRE version is set to 1.4 . I have to reset it to 1.6 / workspace default manually.
Facets configuration is not stable. Some configurations have to be done manually and in a specific order.
Maybe I can fix them if I read more about it. And I have a more or less serious problem with its WTP extension. I think its important to say, that the WTP extension is not officially supported and may not have production quality.
I know there is another plugin which integrates maven into Eclipse. I did not try it, yet. Is it better?
Also I think, that maven may be useful for much more areas. For example the directory structure could be extended to hold e.g. requirements, specification and modeling artifacts. I think that would only work, if it would be standardized. Revision control for all documents would be nice, too.
So many thing, that could be integrated to support the complete software development prosess. Maybe its unrealistic, to get all of these features. For now the Eclipse integration with WTP and VCS integration have the highest priority for me.
Any suggestions? Thanks in advance.
The directory structure is now independent from Eclipse, but now it is dependent from maven. OK, I see, both programs seem to be quite flexible at this point.
Yes, they are both flexible so we could bend one or the other. But if I had to choose a layout, I would pick the IDE agnostic one i.e. the Maven layout and I would stick to the defaults to minimize the efforts and because they are well known (so anybody familiar with Maven knows where to find things). And if someone wants to use IntelliJ IDEA or NetBeans because he feels more productive with it, he can do it. In other words, I don't see any benefit to use the Eclipse layout.
I am not quite sure, if maven is more dedicated to servers or to client systems, e.g. there is a feature / plugin to generate a project website. Doesn't this make most sense on a server system?
Maven can be used for local builds on developer machines, for central builds on a continuous integration machine. And things like generating a website, deploying artifacts are usually done on the central server.
How to integrate maven with a version control system (VCS), e.g. SVN? I think of a system where there is a repository and always up-to-date website with download section for development artifacts.
I didn't really understand the first part of the question. How do you want to integrate Maven with SVN exactly (there is the maven-release-plugin but I'm not sure that's what the question is about)? For the second part, the traditional approach is to use a continuous integration server to trigger a build after a change in the VCS and to deploy (in the maven sense) the created artifacts to a "corporate repository". Many people use Hudson as CI server.
When I generate new Java projects the JRE version is set to 1.4 . I have to reset it to 1.6 / workspace default manually.
That's because the maven project itself is not configured to use 1.6 level (the Eclipse configuration is derived from the POM, which makes sense). You have to configure the maven compiler plugin for 1.6. Here is one way to do it (there are plenty of previous questions on this topic):
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
And then update your project configuration under Eclipse via right-click then Maven > Update Project Configuration.
Facets configuration is not stable. Some configurations has to be done manuel and in a specific order.
They are for me and again, they are derived from your POM (e.g. from the version of your web.xml).
And I have a more or less serious problem with its WTP extention. I think its important to say, that the WTP extension is not officially supported and may not have production quality.
Huh? Where did you read this? Works fine for webapps for me.
I know there is another plugin which integrates maven into Eclipse. I did not try it,yet. Is it better?
I don't have experience with Eclipse IAM. But what is your problem with m2eclipse?
Also I think, that maven may be useful for much more areas. For example the directory structure could be extended to hold e.g. requirements, specification and modeling artifacts. I think that would only work, if it would be standardized. Revision control for all documents would be nice, too.
You're free to put whatever you want in your project tree. Many people are doing this and referring to docs from the site. Possibilities are endless.
Some random points to push you in the right direction:
The standardized directory structure seems also to be nice, but Eclipse has a standard directory structure, too
Eclipse does not have a "standard" directory structure. For example, some people put their unit tests in src next to their code, and others put it in a separate dir like tests or test. You can configure either up as much as you want, but Maven follows has defaults that almost everyone follows:
source in src/main/java
tests in src/test/java
resources necessary for running in src/main/resources
language files
Spring config files
resources necessary for running tests
golden results
config files in src/main/config
Eclipse is an IDE, and Maven is a built build management tool
case in point: if you ask Eclipse to build a JAR/WAR, you have to manually tell it what to include and where. Because you placed your files in Maven's defaults, you get things like:
JARs/WARs contain the compiled Java classes from src/main/java, but not the ones from src/test/java
config files from src/main/config don't go into the JAR/WAR (kinda defeats the purpose of a config file if it did)
test resources from src/test/resources don't go into the JAR/WAR
if you decide to build an assembly (Maven speak for a distribution of your code you can put on your website that includes documentation, source, binaries, etc.), it can make a JAR, the config files, and javadocs into a ZIP file.
I am not quite sure, if maven is more dedicated to servers or to client systems, e.g. there is a feature / plugin to generate a project website.
Yeah, the Maven site plugin.
Doesn't this make most sense on a server system?
Not really. Documentation is critical for any project, especially for client systems.
Maybe I can fix them if I read more about it. And I have a more or less serious problem with its WTP extention. I think its important to say, that the WTP extension is not officially supported and may not have production quality.
Because Maven integration with Eclipse via the m2eclipse plugin isn't perfect, I actually won't use it for WTP projects. I use the Maven Eclipse plugin to generate Eclipse project files and then import the project as a regular Eclipse project. The downside is that the Eclipse project files have to be re-run after any significant changes to the project.
Revision controll for all documents would be nice, too.
That's not Maven, or any build management tool. That's your SCM, Subversion or whatever.
When I generate new Java projects the JRE version is set to 1.4 . I have to reset it to 1.6 / workspace default manually.
You can set that through Maven.
Maybe its unrealistic, to get all of these features. For now the Eclipse integration with WTP and VCS integration have the highest priority for me.
The m2eclipse plugin and friends work best for simple Java Maven projects. Personally, I use the Maven eclipse plugin to generate an Eclipse project for any web, EJB, etc. projects.
There's downsides to that as mentioned earlier, but the upsides, including dependency management as you mentioned, outweigh them, IMHO.
Of course, a poorly configured Maven project is still a poorly configured project. It's not magic. :)