As described in this post I have been unable to successfully run any code from the book "Stream Processing with Apache Flink, including the precompiled jar.
It is not my practice to use an IDE but I thought I would try to use IntelliJ as Chapter 3 "Run and Debug Flink Applications in an IDE" describes how to do that specifically for the code for this book.
The book describes a project import process that I have not found a way to use. It describes setting options on import, for example select Maven. I have not found a way to set any options on import.
I am able to import a project and run code. The code fails, looks like with missing dependency. Maybe because it isn't a Maven project?
Here are steps to reproduce
git clone https://github.com/streaming-with-flink/examples-scala.git
Start IntelliJ
Choose "Open or Import" and Select the "examples-scala/" folder. The project imports with no chance to select options.
Now I have a project
Browse to AverageSensorReadings class, open, and run.
Errors with
java.lang.NoClassDefFoundError: org/apache/flink/api/common/typeinfo/TypeInformation
How can I run this code in IntelliJ?
I see that flink dependencies have provided scope in Maven - this means that thay are not included into the classpath when you running the application. Most likely the application is meant to be run on environment where these dependencies already exist (e.g. Hadoop). To be able to run it from from IDE set Include dependencies with "Provided" scope option in Run Configuration:
Related
I don't understand exactly what is the way of working with maven projects in Eclipse.
The problems I have are often with projects I download from github. If I set the project myself it usually work, so I think I'm doing something different from the majority of people.
I'll try to detail a specific case:
I clone a repo, let's say: https://github.com/spring-guides/tut-spring-boot-oauth2
In Eclipse I import "existing maven project"
The project has a "Maven nature" as indicated by M on the folder icon
I try to run java class with main from Eclipse. First strange thins is that the "Run As" menu doesn't have "Run as a Java application"
I have to configure the configuration manually. Now it runs, but strange things happens, like I can't edit the file as the "content assist" throw errors instead of giving the normal assists.
I notice that the project has no "source folder". So my first instinct is to add a Java nature or select src as source folder
So I add Java nature to the project. This is a disaster. It can compile anymore as it can find packages. All classes have errors. I try to play around setting source folders on /src or /src/main/java. Sometimes I fix the errors but I can't run (and now I have run as Java application) but when I run it can't load the class
So in the end, I'm a bit confused and I don't know if I explained clearly what I'm doing.
I think I would like to know in a simple way how people are doing it, rather than trying to correct my steps as I'm probably creating a mess myself.
Any help or suggestion welcome.
I'm using the last version of eclipse. I don't know which other tool's versions are relevant.
P.S. I also refresh,restart,clean rebuild the project often after touching things...but it doesn't get better
Maven is a build (management) tool. Simply spoken, its task is to create a JAR that can be used as a dependency/library by other projects or when running java -jar ....
Running a project's code isn't part of it (apart from unit and integration tests code and by using non-default plugins for special situations). Running code is part of Eclipse (or any other IDE) with its Run Configurations.
I’m trying to open the Apache Spark source code in IntelliJ IDEA.
I opened pom.xml on the Spark source code root directory.
Project tree is displayed in the Project tool window.
But, when I open a source file, say org.apache.spark.deploy.yarn.ClientBase.scala, a lot of red marks shows on the editor scroll bar. It is the ‘Cannot resolve symbol’ error. Even it cannot resolve StringOps.format.
How can I fix it?
On File | Project Structure window, the following error message is displayed with pink background:
Library ‘Maven: org.scala-lang:scala-compiler-bundle:2.10.4’ is not used
Can it be a hint?
The versions I’m using are as follows:
OS: Windows 7
IntelliJ IDEA: 13.1.6
Scala plugin: 0.41.2
Spark source code: 1.1.1 (with a few file modified by me)
I’ve tried to fix this and error state changed somewhat, but eventually I gave up fixing it on my own (with googling) and deleted .idea folder and started over. So now I’m seeing the errors described above.
UPDATE:
I noticed thw following popup:
Maven projects need to be imported: Import Changes Enable Auto-Import
And enabled auto-import according to the articles IntelliJ: Maven projects need to be imported: Import Changes Enable Auto-Import and http://javafortesters.blogspot.kr/2013/09/do-enable-auto-import-in-intellij-for.html . Now IntelliJ resolves base Scala symbols.
But still it cannot resolve a few symbols.
The notable file is yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ClientBase.scala. In this file, ClientArguments class is not resolved. IntelliJ suggests importing org.apache.spark.deploy.ClientBase, but in fact ClientArgument class is in the same package with ClientBase - that is, org.apache.spark.deploy.yarn.ClientArgument.
Why IntelliJ confuses this?
Thank you.
You need to change the Scala compiler from IntelliJ to “sbt incremental compiler” (see the screenshot below).
You can access this by going to “preferences” -> “scala”.
NOTE: This is supported only for certain version of IntelliJ scala plugin. See this link for details.
http://blog.jetbrains.com/scala/2014/01/30/try-faster-scala-compiler-in-intellij-idea-13-0-2/
Seems your maven cannot download jars according to your pom dependencies setting.
Two possible factors:
It could be due to your network, so you need check with proxy setting: (Ctrl+Shift+A in IntelliJ, enter "proxy", to check it connection).
It could also because your maven home has not been set in IntelliJ. to set it, you need (Ctrl+Shift+A in IntelliJ, enter "maven setting", to set maven home to point to the place where you have installed your maven.
Background
I'm currently trying to extend Junit (org.eclipse.jdt) in order to do some tracing.
Therefore I created my own plugin project which (among others) provides a class which should be used by the junit runtime plugin.
I have setup my project as a dependency for junit and the package containing my class is listed as "exported" in my Manifest in the runtime tab. If I run the plugins as an eclipse application everything builds and starts allright and.
Problem
However, if in the started eclipse I perform a "Run as Junit", I get a NoClassDefFoundError concerning my class. In my understanding this means, that at runtime my class is not visible in the started eclipse. I thus printed the classpath while running and like expected my plugin doesn't show up.
Do I have to add my plugin to the "runtime" settings of the junit plugin? In the Manifest, my package is not available under the "export -> add" button. I tried importing a jar of my plugin and configuring those exports manually here, but this did not help either.
My thought process kind of gets stuck with this "run in run" configuration...
Any help is welcome!
Digging deeper in the code I found that the reason for the error is, that the part which calls my code and throws the error is run in a seperately started VM which has its classpath set via code. Nothing was wrong with the configuration, it just was not used in this case.
So if you ever stumble upon a "VMRunnerConfiguration" while having classpath problems, this might be your problem. ;)
I would just like to setup a new GWT project in Eclipse and use Maven for dealing with all the jar jungle. I used gwt-maven-plugin with this instructions, but I can't get the project to work in Eclipse.
What I've actually done:
Created a maven project using the archetype gwt in command line.
Imported the projet in eclipse using import > existing maven project
While doing that I had errors saying:
gwt-maven-plugin:2.3.0-1:generateAsync - "No marketplace entries found to handle"
gwt-maven-plugin:2.3.0-1:i18n - "No marketplace entries found to handle"
gwt-maven-plugin:2.3.0-1:exploded - "No marketplace entries found to handle"
These errors don't go away even if I ignore them on the import.
How can I make these projects working? Is the problem that I skipped the "process-resources" setting? (There is no such setting in the latest version of m2e.)
Should I even use gwt-maven-plugin? Is there any other way of making a GWT project to use Maven? Or – is there any other way to fight with the jar jungle? What does GWT guys use?
I use Eclipse Indigo with m2e plugin 1.0.0 and Google suite plugin version 2.3.3.
Eventually I gave up Maven. As one other developer said "good ideas and bad code build communities faster" , I also remember my experience with Maven on all the projects: very promising on the beginning, but eventually you get to some problems and end up working more with configuring Maven than actually dealing with your own code.
I decided to manually copy needed .jar-s into /lib folder. I spent some time due to transitive dependencies, but LESS than dealing with Maven and now I have things under control. If sometime in the future working with libraries will become an overhead, I will consider using Ivy.
If someone wishes to stick with Maven, I lately found a very useful link by Google team:
http://code.google.com/p/google-web-toolkit/wiki/WorkingWithMaven
They recommend using their sample projects and not gwt-maven-plugin archetypes (due to issues). I agree. They also provide needed pom lifecycle changes for Eclipse Indigo.
According to a recent post on the gwt-maven-plugin mailing list the Maven integration is not complete for Eclipse Indigo, since the M2Eclipse 1.0 release has brought about a large number of changes. The suggested workarounds from David Chandler, Google engineer, are:
You can run "mvn package" on the command line or right-click on the project > Maven > Run as > Maven build.
The plugin execution failures you're seeing can be resolved by adding lifecycle mapping metadata as in the sample POMs. They are only needed for Indigo. You should not get these errors in Helios or when running mvn package from the command line.
Disclaimer: The following guidelines are for Windows users. These steps are on the basis that, they have worked when tried by the replier and doesn't guarantee fulfledge working unless experimented by self and tried with proper prerequisites.
::Creating a simple gwt project using archetype::
Following are few commands that can be used to create a simple gwt project "Web Starter Application":
mvn archetype:generate -DarchetypeGroupId=org.codehaus.mojo
-DarchetypeArtifactId=gwt-maven-plugin -DarchetypeVersion=2.3.0
mvn -DarchetypeGroupId=org.codehaus.mojo
-DarchetypeArtifactId=gwt-maven-plugin -DarchetypeVersion=2.3.0 -DgroupId={project packaging} -DartifactId={application name} -Dversion=1.0 org.apache.maven.plugins:maven-archetype-plugin:generate
mvn -DarchetypeGroupId=org.codehaus.mojo
-DarchetypeArtifactId=gwt-maven-plugin -DarchetypeVersion=2.3.0 -DgroupId={project packaging} -DartifactId={application name} -Dversion=1.0 -Dmodule={module name} org.apache.maven.plugins:maven-archetype-plugin:generate
(The value of archetypeVersion can be 2.3.0 or any higher stable version.)
Few coordinates are required by maven to create the gwt project. They are as follows:
groupId
artifactId
version
module
The first command doesn't take any of the above coordinates hence, we need to supply them at the time it executes. Notice that the archetype goal is mentioned right at the beginning of the command. It is mandatory to give the archetype goal.
The meanings of these coordinates can be found here.
One of the best ways to start with understanding maven is this.
The second command doesn't consider the module name hence, you will be prompted to give it at the time the command executes.
The third command is equivalent to running it in batch mode where you just have to confirm the inputs for groupId, artifactId, version, module as mentioned in command itself.
Once any of these commands gives a BUILD SUCCESS result, then navigate to the just-now-created project folder from command line and execute the following command:
mvn gwt:run
It should start the project in Development Mode so that you can Launch the Default Browser to run the project or Copy the URL to clipboard and navigate to it through any browser.
Good luck with the execution.
I have just upgraded my SpringSource Tools Suite (STS, a variant IDE of Eclipse) to the latest version (v3.6.1). Then all my JUnit unit tests can not be run again. I am getting this error:
Class not found ClassToTest
java.lang.ClassNotFoundException: ClassToTest
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
According to this blog:
ClassNotFoundException when running JUnit unit tests within Eclipse (using Maven),
it is because of some misconfiguration of Maven plugin in Eclipse. However, in STS 3.6.2 I cannot find this option "Include Modules" in the Maven plugin. How can I fix this problem and re-enable my unit tests?
There are still some back-draws on the current m2e plugin. Unit-test-cases couldn't be run as their including project grouped in a working-set. Following may help:
Right click on project including junit-tests.
Select Maven -> Disable Workspace Resolution
Try then to run your test again.
OK it seems I'll have to answer this question by myself.
The main reason for this problem is still the m2eclipse eclipse plug-in. The new version of this plugin does not support nested modules in one project. If we really need to see multiple modules we have to remove the old one from the package explorer and create a working set and import the project again using the option "import existing maven projects". The eclipse import wizard will pop up a window and ask you which module to be imported. Then we can select all the modules and finish the import. As a result the working set will contain all the modules of your project and treat each module as a separate project, although in the workspace your modules are still in one project. By doing this it resolves all the problems that I have come across in Eclipse related to classpath, such as not being able to search a class or not being able to run the unit tests and get a java.lang.ClassNotFoundException.
For reference, here is an article to teach you how to create a working set:
Working set
I think you can import the project without creating a new working set but the working set will keep all the modules that belong to your project in one set so it is easier to organize.
I wish I had the answer two months ago so I wouldn't have spent much time searching for a solution.
I think I have found the solution, at least this worked for me:
right click on the project and choose 'Maven' -> 'Update Dependencies'
Then when I tried , I did not get ClassNotFoundException .
I tried everything mentioned here and in other posts. Some of the solutions that people proffered were:
Change the output folder for the test classes.
Create a custom builder for the project that would run test-compile from Maven.
Move the Maven dependencies higher in the Order and Export list in the project build path.
There were many, many more but the one that I found to work was as follows:
Close the development environment.
Delete the jars used by the project from my local Maven repository.
Open the IDE.
Build the project.
Run the test.
After hours of beating my head against my keyboard and following suggested solutions, this one worked!
We too faced the same ClassNotFoundException while trying to run JUnit test class. But when we tried using the following steps, it successfully started running.
Select your project.
Click on the project option displayed in toolbar in the eclipse IDE.
Select “clean”.
Now try running the test file.
As a work-around, try running mvn test-compile (either in Eclipse or from the command line), then try running the Junit test within Eclipse.