I'm trying to set up my first scala lift project in Eclipse and it is Not Simple (TM).
What I have done is set up the project trough Maven with the following
mvn archetype:generate -U \
-DarchetypeGroupId=net.liftweb \
-DarchetypeArtifactId=lift-archetype-basic_2.9.1 \
-DarchetypeVersion=2.4-SNAPSHOT \
-DarchetypeRepository=http://scala-tools.org/repo-releases \
-DgroupId=demo.helloworld -DartifactId=helloworld -Dversion=1.0-SNAPSHOT
I then created an eclipse project from this with mvn eclipse:eclipse (because it's hellish to figure out all the dependencies, and add them all to the build path manually)
The project then conflicts with the installed Scala version. So I removed the three existing references to scalalang from the buildpath, and added my own scala to the buildpath. I'm using scala 2.9.0.
Now the project can be built, but when I try to run RunWebApp, an exception is thrown:
Exception in thread "main" java.lang.NoClassDefFoundError: RunWebApp
Caused by: java.lang.ClassNotFoundException: RunWebApp
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: RunWebApp. Program will exit.
I'm aware of the answer on Scala-Lift project in Eclipse Scala IDE errors suggesting to ask the question on http://groups.google.com/group/scala-ide-user yet I hoped someone here could point me to the answer in a way someone else with the same problem might find the answer too
I advice you to use lift with sbt. You can find template project here https://github.com/viktortnk/lift-quickstart with sbt 0.11.2 and lift 2.4
It also includes sbt eclipse plugin to work in scala-ide.
I hope it will help you.
I find if you use sbt 0.11 and the sbteclipse plugin, it does all the magic for you.
https://github.com/harrah/xsbt
https://github.com/typesafehub/sbteclipse
I know this question is old, but it comes up in the search results pretty high, so I wanted to add an updated answer.
The latest Scala IDE (2.1 M3) is getting quite good, as are the maven integrations. I have an open-source demo project at:
https://github.com/awkay/lift_squeryl_demo
that gives instructions on getting eclipse set up with the following features:
Simply Import a lift project based on this pom (which uses Scala 2.9/Lift 2.5) As "Existing Maven Project". Done. Nothing else to run. No sbt files to generate. No eclipse project files to generate...it just works.
Great scala support, including highlights on implicits, great source level debugging
Web tools server support (run/debug your webapp in the servers tab of eclipse)
JRebel support for on-the-fly class reloading (there is a free license for this!)
Typical maven support for command-line builds and packaging
The ability to any number of Java webapps on the same tomcat instance, in cases where you have to deal with integration among apps.
The result is an experience that requires no command line interaction at all, and includes super-fast edit-save-reload web development. It really gives you the dynamic language development experience.
I don't know if this is the problem you're having, but sometimes you need to make sure the Scala library appears before the JRE library in the project classpath (or run configuration used to execute it).
http://www.assembla.com/spaces/scala-ide/tickets/1000119-classnotfoundexception-trying-to-run-scala-app-in-helios
Related
So far I've been running IntelliJ IDEA Community Edition for my Scala projects, but as my projects are expanding in complexity, I stumble upon more and more roadblocks with the IDE.
Like for example the simple fact that IDEA doesn't allow for web-development or Java EE development what so ever, which means using the Play Framework or TomEE in Community Edition leads to nothing but dead ends and frustration.
The only reason I switched to IDEA in the first place, is because of its excellent plugin system, allowing me to run SBT seamlessly as the primary scala compiler and library downloading tool with ease.
Searching around on Google, however I can only seem to find mentions about the eclipse plugin for sbt, that makes an sbt project Eclipse friendly, which is the exact opposite of what I'm really looking for.
I'm not willing to spend €89 per year for a student licence after all the pain it's put me through so far...
So my question is; is there a plugin for Eclipse that allows me to use SBT the same way as in IDEA? Or am I forced to go through the console?
There may be some movement in this direction in the future, but for now there is no such plugin.
Currently there is no Sbt plugin for Eclipse. Depending on your use-case, you could:
use the Eclipse builder
Pros: proper integration (error markers in Problems and editors, cancelation, progress reporting)
Cons: may get out-of-sync with the Sbt build file (when adding a dependency, for example), doesn't handle anything other than Java and Scala (like Play templates or route files)
use Sbt on the command line (make sure to disable auto-building in Eclipse)
Pros: can handle complex builds, classpath is always up to date
Cons: no integration (see above)
use Activator
Same Pros and Cons as Sbt, but with a pretty UI
We are working on an sbt-server plugin for Eclipse, which will delegate the build to an external Sbt process without giving up the convenience of integration. We hope to have something out towards the end of this year.
I think the main problem you are trying to solve for is too have sbt jar dependencies show up and get used natively by your eclipse project. You can do that with the IvyIDE plugin (which is found in the eclipse marketplace).
If you have that installed (and the eclipse plugin for sbt) then this closes the gap between systems.
To enable:
type the {sbt deliver-local} command from your terminal. This adds an ivy xml in your project's target directory
right click on your project. Choose the Ivy -> enable Ivy dependency management option
go into your projects properties. Highlight the Ivy property. Click the new button and navigate to the ivy xml file in your projects target directory.
Now your eclipse compiles off of your sbt managed dependencies and now you are doing everything you want except actually running sbt from within eclipse (which you only have to do now when you are changing dependencies)
Ok, I need some help in setting up a Scala project with IntelliJ, I have download and installed the project successfully, but i have had issues when it comes to installing the Scala compiler itself, WHen i go to configure a new Scalaa project and choose to set the Scala home, I choose the download Scala option and i get the following error "downloading failed, connection failed with error 404: http://www.scala.lang.org/downloads.distrib/files/scala2.10.0+RC2.tgz" i have tried downloading the things, such as primefaces and jSF through intelij, and they all work fine, any suggestions?
Download Scala manually and just select proper directory in new project window.
http://www.scala-lang.org/download/
You should be using SBT to define and build your project. Among other things, it handles retrieving the Scala compiler and libraries. IDEA is similarly self-contained as far as its Scala plug-in's internal Scala compiler is concerned. By using SBT and IDEA (see below for connecting the two), the only thing not covered is a Scala REPL for use outside of either SBT or IDEA. If you're using a Mac, Homebrew includes a Scala formula. Because SBT retrieves the Scala compiler and libraries for the version of Scala you specified, everything is self-contained.
By far the best way to build and maintain IDEA project definitions for Scala projects is with the sbt-idea plug-in for SBT. Once you install that plug-in, which is trivial, you simply use the gen-idea SBT task it provides. When your dependencies change, you run gen-idea again to update the project.
Trying to get a lift project to run on windows, I've installed maven on my computer, then tried to use
mvn archetype:generate from cmd, then chose the lift basic one , but it always failed on the jetty:run part. Before that, I had to change a lot of the pom.xml file to even get a successful build (since the tutorial I was using was obsolete and it couldn't find the dependencies).
So I've decided to try with the eclipse plugin, thinking it should be easier.
I've installed the maven plugin for eclipse and created a project with the lift archetype.
The project was succesfully created, but I have all kinds of errors in the editor for missing ; and so on (I have scala ide installed on eclipse also and creating a normal scala project works and compiles/runs fine). I have also tried to include the scala-library.jar in the buildpath, with no change.
The odd part is that I can run the cmd and go to the project folder, then run mvn jetty:run and it will actually work (?!) Trying to run in eclipse with jetty:run as goal will give me ClassNotFoundException on the HelloWorld snippet.
So what might be wrong with my settings?
UPDATE: no luck whatsoever, after trying 3 different eclipse versions, installing the maven for scala plugin and following every tutorial I could find. It just simply feels all is outdated on the instructions:
this is how it looks after I include the scala libraries for eclipse on every project (after I create it from an archetype):
is this "mvn archetype:generate" up to date? I don't know if anybody guarantees it will work at all..
Anyway, the default way to at least try Lift and see it working is the following: https://github.com/lift/lift_25_sbt
It uses "Simple Build Tool" instead of maven, but maven should work, too. Also, you can easily read "build.sbt" to get all the dependencies.
Plugins for creating eclipse/intellij project definitions are included. (See the README of the demo project.)
The target to create eclipse project is "eclipse" or "eclipse with-sources=true".
The target to launch the app is "container:start".
I am using the eclipse plugin for maven to generate eclipse projects from maven pom.xml files.
mvn -Dwtpversion=1.5 eclipse:eclipse
This works fine and, after some experimenting with several of the 400 different archetypes available, I settled on using the webapp-javaee6 archetype, which was the only one which generated a set of dependencies that were both all available and which created a project that was useable by the WTP plugin.
The problem now is that I would like to be able to invoke mvn goals from eclipse. The accepted way to do this I understand is to use the m2eclipse plugin, which I have installed.
However, after playing around a bit and getting nowhere I discovered this comment in my .project file:
<comment>NO_M2ECLIPSE_SUPPORT: Project files created with the maven-eclipse-plugin are not supported in M2Eclipse.</comment>
Further searching (see this lengthy diatribe from October) suggests I'm not (just) being stupid in not being able to get this to work.
The how-to linked in the top answer to this question seems hopelessly out of date.
So, the real question - what is currently the correct way to use maven to generate a WTP-friendly project that can be converted to eclipse and then use eclipse to call the project's goals?
Have you tried File -> Import -> Check out existing Maven Projects from SCM? My understanding is that m2eclipse will then create the eclipse project for you. If the packaging defined in the pom is war, the project should be deployable with WTP. (The latter used to require an the maven-wtp-integration plugin as well, don't know whether that's still the case).
Not sure about WTP or maven archetypes, but have you come across SpringSource Tool Suite (Spring packaged eclipse) and created a Spring Roo project? You can use this to create a data driven maven built web-app in a few mins. You can even remove the spring roo bits if you don't want them, it will give you a good starting point for a web-app with very little pain.
Does anybody have experience working with JavaRebel, specifically for a large web application built using Maven? There is a JavaRebel plugin for Maven that seems under-documented, does anybody have comments on how it works, can you really update one class in a Multi-module Enterprise Project and have it "automagically" change on your Server?
Are there any issues with different IDEs and this setup? For example NetBeans will not let you compile one class at a time in a Maven project (from what I can tell).
Disclaimer: I work for ZeroTurnaround.
JRebel (formerly JavaRebel) installation involves the application configuration file "rebel.xml" and modifying the container startup command line.
The Maven plugin is used to generate the "rebel.xml" file, that is used by the JRebel agent running in the container to find the files in the workspace. This allows to use IDE building to compile .java files and skip the Maven build process, as the changes to files will be picked up from the workspace. However as it relies on the IDE to compile the classes, it does depend on the IDE ability to compile efficiently. I know for sure that Eclipse will compile classes one at a time and am fairly sure you can configure NetBeans and IntelliJ IDEA to do the same.
In addition to the Maven/rebel.xml configuration you also need to configure the container startup command line. You may also need to install and IDE plugin or do some additional configuration to have the best expirience with JRebel. Following through the steps of Installation manual ensures that.
Hope this helps.
Disclaimer: I've not actually used this plugin myself.
This tutorial implies that JavaRebel works well with Eclipse 3.4. If you are also using m2eclipse it should work ok with Maven projects as well (as long as you ensure that Maven and Eclipse are compiling to the same target folder so the Eclipse incremental compiler can be used to modify the class file).
According to this post, you should configure the javarebel-maven-plugin to generate the rebel.xml (used to mount external folders to the application classpath). There's also a general installation guide you may find useful.