Import Maven dependencies in IntelliJ IDEA
I have a small question about IntelliJ IDEA 11. I just imported a project from subversion - its a maven project. But I have a problem in maven library dependencies so that I can't include all maven dependencies automatically - IDEA shows dependency errors only when I open that class/ Thats what I get here:
So I want all dependencies to be added automatically - is that possible or do I have to go through all class files to identify and add maven dependencies?!
UPDATE: After doing some modifications I found how to resolve my problem in some way. Thats what I did: 
but I think logically it will not include and check new dependencies ahead?!... Is there any settings area for this in intelliJ - auto export dependencies to classpath ?!
IntelliJ should download and add all your dependencies to the project's classpath automatically as long as your POM is compliant and all the dependencies are available.
When importing Maven projects into IntelliJ an information box usually comes up asking you if you want to configure Auto-Import for Maven projects. That means that if you make any changes to your POM those changes will be loaded automatically.
You can enable such feature going to File > Settings > Maven > Importing, there is a checkbox that says "Import Maven projects automatically".
If that doesn't help, then I would suggest to make a full clean-up and start again:
*.iml files and all .idea folders (there should be one per module) mvn clean install from the command line IntelliJ 2016 Update :
The Import Maven Projects automatically setting has been moved to Build, Execution, Deployment > Build Tools > Maven > Importing in your IntelliJ preferences.
Thought I'd throw my $0.02 in here: For me, the fix to this was to go to
File [menu] -> Settings -> maven -> importing and uncheck "use maven3 to import project"
ref: http://youtrack.jetbrains.com/issue/IDEA-98425 (which may have a few other ideas too)
Update: Ran into this again, with IntelliJ 15 this time, which has no "use maven3 to import" option available anymore. The cause was that sometimes IntelliJ "doesn't parse maven dependencies right" and if it can't parse one of them right, it gives up on all of them, apparently. You can tell if this is the case by opening the maven projects tool window (View menu -> Tool Windows -> Maven Projects). Then expand one of your maven projects and its dependencies. If the dependencies are all underlined in red, "Houston, we have a problem". 
You can actually see the real failure by mousing over the project name itself.
In my instance it said "Problems: No versions available for XXX" or "Failed to read descriptor for artifact org.xy.z" ref: https://youtrack.jetbrains.com/issue/IDEA-128846 and https://youtrack.jetbrains.com/issue/IDEA-152555
It seems in this case I was dealing with a jar that didn't have an associated pom file (in our maven nexus repo, and also my local repository). If this is also your problem, "urrent work around: if you do not actually need to use classes from that jar in your own code (for instance a transitive maven dependency only), you can actually get away with commenting it out from the pom (temporarily), maven project reload, and then uncomment it. Somehow after that point IntelliJ "remembers" its old working dependencies. Adding a maven transitive exclude temporarily might also do it, if you're running into it from transitive chain of dependencies."
Another thing that might help is to use a "newer version" of maven than the bundled 3.0.5. In order to set it up to use this as the default, close all your intellij windows, then open preferences -> build, execution and deployment -> build tools -> maven, and change the maven home directory, it should say "For default project" at the top when you adjust this, though you can adjust it for a particular project as well, as long as you "re import" after adjusting it.
Other things that might help: deleting your intellij cache folders (windows: HOMEPATH/.{IntellijIdea,IdeaC}XXX linux ~/.IdeaIC15) and/or uninstalling and reinstalling IntelliJ itself. GL!
Try to Re-Import the project from the Maven Projects panel in IntelliJ IDEA. It should download and configure all the dependencies defined in your pom.xml automatically.
If download doesn't work from IDEA for some reason, try mvn install from the command line and see if the dependencies can be fetched.
Of course all the required dependencies and any custom repositories must be defined directly in the pom.xml file.