Eclipse mars is too slow.. Always busy in scanning classpath - eclipse

I am using eclipse mars 4.5. Problem is, it always busy with scanning class path that actually makes eclipse too slow to work on. I am working on the multimodule OSGI projects, so there are around 30 projects in the workspace and eclipse every time starts scanning classpath for all projects.
can anybody help to optimize the eclipse and stopping auto class path scan for each project.

On my machine the vaadin designer scanned each projects of my workspace (in my case about 100 bundles), and this took very long (eclipse Mars.2 and Neon)
Hint: open visualvm - connect to eclipse pid; create a thread dump and analyze the worker threads of eclipse.

I have the same issue and the only things I do are:
Maven plugin:
If you use the maven plugin, on each project, choose the Maven option Disable Workspace Resolution the other project will not refers anymore those in the workspace.
Apparently this is a known bug and you can find some more solution like rebuilding the maven indexes here.
Maven in command line:
Another option I choose is to use the maven on command line (It's not perfect but in the environment I work in it is the best solution) and use the option "Offline" in the maven preferences. This is due to proxy which is not working from Eclipse but work from command line (my setup).
Personally I use both option but this is due to a very strict proxy which is not friendly; I think this is a good setup for OSGI as trying to resolve all dependencies could be very long.
Another point: try to see if you have circular dependencies, it can happens very quickly in OSGI environment and I guess that can also make the compiler to be mad.

Related

How do I run SBT from within Eclipse?

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)

Eclipse stopped deploying any of the project's [maven] dependencies to tomcat

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.

m2eclipse and Eclipse WTP

I have a very large workspace with about 30 projects all together. I am using Eclipse 3.5 with m2eclipse. I check out of my subversion repository using the defaults in order to import the projects into my workspace.
I create a Tomcat server instance, and publish my web project to the tomcat server. Sounds easy enough.
The problem is that it does not appear as though the transitive dependencies for my other projects are being automatically added to the container, so when the container starts up I get classnotfound exceptions, etc.
I go into the web project's properties, and I notice that the Java EE Module Dependencies are NOT checked for some of the transitive dependencies. I check them, and everything seemingly works until I do a project clean build, when the Java EE Module Dependencies are automatically reset by eclipse, so I need to recheck them. This is maddening, and I was hoping there was some way to automatically pull in all of the transitive dependencies when working with Eclipse WTP.
I should mention, using standard maven build works just fine, and everything gets pulled in appropriately into the resulting WAR file. It just doesn't work so good with WTP for some reason.
You need to make sure that you have "Maven integration for WTP" feature from m2eclipse installed. There is a simple tutorial available at http://docs.sonatype.org/display/M2ECLIPSE/WTP+mini+howto
What version of WTP and m2eclipse you are using? Check that dependency version declared in project's pom.xml matches with version declared in workspace project and make sure that workspace dependency resolution is enabled.
Also, you can try to run "Maven / Update project configuration" from the project popup menu and check that there is no errors on Maven console and in Eclipse's own log.
If the above won't help, try to reproduce issue on a smaller project and then submit it with a bug report
It appears as though the latest version of m2eclipse (.99x) solves all of my issues.
If you are tempted to use m2eclipse wtp extras you need to be aware that they are not supported by Sonatype and, although mostly OK, are not 100% robust.
See http://maven.40175.n5.nabble.com/What-is-the-recommended-alternative-to-m2eclipse-extras-WTP-integration-td135727.html

JavaRebel with a Multi-module Enterprise Project in Maven

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.

synchronising / maintaining ant and eclipse classpaths

I'd be interested to find out about any automated processes that people have for ensuring that the project classpaths for the ant and eclipse configurations are in synch. In my case, I want the classpath defined in the ant build file to be the master configuration, since its used for our production builds. As part of the build i'd like to add an ant target that will verify that the eclipse classpath is up to date, or at least indicate differences between the two classpaths.
I'm aware of ant4eclipse but its focus is in the opposite direction, ensuring that the eclipse classpath is master and that the ant build reuses the eclipse path. I like the idea behind AntAndEclipse but am wondering are their ant other tools in this space that i'm not aware of.
You solution at a previous company was to have ant invoke Eclipse to do the compiles as described here:
http://www.eclipse.org/articles/Article-PDE-Automation/automation.html
I'm not aware of any ant tools which can do this but I've switched from ant to Maven a few years ago and never looked back. You can use the "Maven integration for Eclipse" to make Eclipse use the Maven classpath.
As of today, I'm not 100% happy with the Eclipse plugin, though. It's a bit slow and due to the different philosophy of Eclipse and Maven, some operations behave strange. For example, Eclipse doesn't differentiate between a "production" and "test" classpath, so you can get compile errors in Maven when everything looks great in Eclipse.
My solution was to use the plugin to keep the classpath in sync and compile from the commandline.
there is an ant task to do xml transformations, we used that task to create the classpath in our build file. It was a little trick to get the XSL right but once it worked it was great
Did you evaluate Apache IVY? Currently I am building a Continuous Integration environment at our place and we use IVY to handle our dependencies. There is a eclipse plugin that takes the dependency configuration of eclipse and uses it as eclipse classpath.
Currently this solution looks quite promising.
My team wrote an Eclipse plug-in to add a new type of library to the Java Build Path->Add Library option in the project settings. This custom library type allowed both Eclipse and ANT to reference the same canonical list of dependencies.
Nowadays, I'd probably look at IVY for doing the same thing if I was locked into using ANT, rather than writing my own.
You need Ant2Eclipse.