This problem happens intermittently for different libraries and different projects.
When trying to import a library, the package will be recognized, but the class name can't be resolved.
If on the import statement, I right-click -> Goto -> the package's declaration, I see all the decompiled classes displayed in the side pane -- Including the ones I need --
If I try to auto-complete the import statement, I notice the class I need is not featured in the dropdown.
I tried invalidating caches already, doesn't work. I cannot find any class conflicts -- there is no other jar file in my classpath with the same package name.
I am able to import this class into other projects.
Please see screen shots:
Anyone have a clue?
You can try invalidating the cache and restarting IntelliJ, in many cases it will help.
File -> Invalidate Caches/Restart
There can be multiple reasons for this. In my case it was wrong source root issue. Invalidate caches didn't work along with other solutions.
Check your module source roots.
Project Structure (Ctrl+Alt+Shift+S).
Modules
Select your problem module.
Change tab on top of window "Sources".
Remove unwanted source roots. Keep one and add src and test source roots in this root.
File -> Invalidate Caches/Restart
And
Build your project
IntelliJ has issues in resolving the dependencies.
Try the following:
Right click on pom.xml -> Maven -> Reimport
Again Right click on pom.xml -> Maven -> Generate sources and update folders
Run this command in your project console:
mvn idea:idea
Done.
Had this issue many times. Tried 'Invalidate Cache & Restart' and all other solutions. Running that command works perfect to me.
I'm currently using IntelliJ 2019.2, but this also happened in previous versions and solution worked as well.
File -> Invalidate Caches/Restart or rebuilding the project did not work wor me.
What worked for my Gradle project was to "Refresh all Gradle projects" from the Gradle tab on top-right corner of IntelliJ v2017, using the yellow marked button shown below:
Check your module dependencies.
Project Structure (Ctrl+Alt+Shift+S).
Modules
Select your problem module.
Change tab on top of window "Dependencies".
Check what needed library (maybe, you need to add specified library
in the tab 'libraries') or module has listed here and it has right
scope ('complile' mostly).
I faced a similar issue, Mike's comment helped me move in the direction to solve it.
Though the required library was a part of the module in my project too, it needed a change of scope. In the module dependency, I changed the scope to "Compile" rather than "Test" and it works fine for me now.
Had the same problem till I noticed that the src folder was marked as root source instead of java!
Changing to only the java (src/main/java) to be the source root solved my problem
I found the following answer from #jossef-harush and #matt-leidholm useful from another link
in IntelliJ editor, click on the red keyword (Integer for example) and press ALT + ENTER (or click the light bulb icon)
select Setup JDK from the intentions menu
click on Configure
In my case, the JDK path was incorrect (pointed on /opt/jdk1.7.0_51 instead of /opt/jdk1.7.0_65)
click on the ... and browse to the right JDK path
let's clear the cache
Right click on pom.xml file, go to Maven click on Reimport. I had similar problem and this worked for me.
After a long search, I discovered that a dependency was somehow corrupted on my machine in a maven project. The strange thing was that the dependency was still working correctly in the compiled java code. When I cleaned and rebuilt my maven dependency cache however, the problem went away and IntelliJ recognized the package. You can do this by running:
mvn dependency:purge-local-repository
Intrestingly, the source of my problem hence wasn't IntelliJ, but maven itself.
For 2020.1.4 Ultimate edition, I had to do the following
View -> Maven -> Generate Sources and Update Folders For all Projects
The issue for me was the libraries were not getting populated with
mvn -U clean install from the terminal.
Try cleaning maven from upstream by:
mvn -U clean install
I also got this error for multiple times when I try to build a new java project.
Below is the step how I got this stupid issue.
Create an empty project, and create new directory src/main/java.
Create the source package net.gongmingqm10.sketch.
Use gradle wrapper, gradle idea to build the gradle stuff for the project.
Add some dependencies in build.gradle file, and gradle build, reimport the project.
Create User.java and School.java in the existing package net.gongmingqm10.sketch
I got the error while I try to use import School in User.java.
Intellij keeps complain can not resolve symbol on import.
Solution:
Build the project first, and mark the main/java as the source root. Create a new directory with the same name net.gongmingqm10.sketch. Move all the files from the old troubling packages to new package.
Root cause:
Directory tree of source code
As you can see from the tree. I got a directory named net.gongmingqm10.sketch. But what we really need is the 3 levels directory: net->gongmingqm10->sketch
But before I finish building my project in Intellij, I create new directory named net.gongmingqm19.sketch, which will give me a real directory with the name net.gongmingqm10.sketch.
When we trying to import it. Obviously, how can intellij import the file under the weired directory with the name a.b.c.
#Anton Dozortsev I was driven crazy by a similar behavior; I ended up re-installing the IDE a bunch of times, only getting past the issue after removing the IDEA app, all caches, preferences, etc.
I tried all kinds of steps in the interim, (like restarts, invalidations, deleting .idea and *.iml files, and others.)
Turns out, the problem was due to IntelliJ's idea.max.intellisense.filesize setting. I had set it to 100KB, which was smaller than my dependency's size, leading to IntelliJ showing it as unknown, just like in your screenshot.
Fix:
Click on Help -> Edit Custom Properties
Set the property to a larger value; the default is 2500KB
idea.max.intellisense.filesize=2500
Please try File-> Synchronize. Then close and reopen IntelliJ before you invalidate.
Once I restarted. I would have invalidated but the synchronize cleared everything after restarting.
Simple Restart worked for me.
I would suggest first try with restart and then you may opt for invalidating the cache.
PS : Cleaning out the system caches will result in clearing the local history.
I found the source cause!
In my case, I add a jar file include some java source file, but I think the java source is bad, in Intellij Idea dependency library it add the source automatic, so in Editor the import is BAD， JUST remove the source code in "Project Structure" -> "Library", it works for me.
What did it for me is to edit the package file in the .idea folder as I accidentally added sources to this jar library and android couldn't resolve it by deleting the sources line as marked in the b/m picture library error.
Then rebuild the gradle and bam problem solved.
I had the same issue and the reason for that was incorrect marking of the project's sources.
I manually created the Root Content and didn't notice that src/main/test folder was marked as Sources instead of Tests. So that is why my test classes were assumed to have all their test libraries (JUnit, Mockito, etc.) with the scope of Compile, not Test.
As soon as I marked src/main/test as Tests and rebuilt the module all errors were gone.
I had this recently while trying to use Intellij to work on NiFi, turned out the issue was that NiFi requires Maven >= 3.1.0 and the version that I'd checked out with (I guess my default) was 3.0.5. Updating the Maven version for the project fixed it, so in some cases Maven version mis-alignment can be a thing to look...I'd guess it's fairly unusual but if you get this far on the thread you're probably having an unusual issue :)
file-> Project Structure -> Modules, find the module with problems, click it and choose the Dependencies tab in the right side. Click the green plus sign, try to add the jar or libraries that cause the problem. That works for me.
Nothing I tried above worked for me (not that I tried every suggestion). What finally did the trick was to rename the class -- I just added a 2 to the class name and filename. Then I resolved all the references manually. (Since they weren't recognized, the refactoring did not change the references automatically.)
Once the "2-version" was happily resolved everywhere, I was then able to refactor and remove the 2 from the class and file, and everything was then as it should be.
in my case the solution was to add the project as maven project, besides the fact that i imported as maven project :P
go to pom.xml -> right click -> add as maven project
My issue was my Maven plugin got disabled after an update. I went to Help -> Find Action... -> Typed in Maven and found that it was "Off". I clicked the toggle switch and after a bit of loading it was re-enabled.
Also, check your class is not in compile exclusions
If you see, that there is a little grey cross in left top corner, you must remove class from compile exclusions
How to remove
Old question, '21 response. I ran into the issue where my go build would build code successfully but my Goland IDE showed missing modules or dependencies. I tried Invalidating Caches and Restart, but had the same problem. From another S/O thread, I tried adding the GO111MODULE=on to my Path Variables, but that didn't resolve the IDE problems either.
What worked for me was picking the correct GOROOT path in Preferences > Go > GOROOT.
I had two versions of go installed, one by brew and one from the online Go installer. I selected the brew install path, and my IDE was able to resolve the dependencies properly.
I've tried all the complicated methods and they didn't work, since I was too lazy to re-import the project I tried something else.
Mine is a gradle project, so I went to my gradle.build file, removed the dependency, refreshed the dependencies, then added the dependency again and refreshed again, the imports started working after that.
Faced similar issue,
I Updated Intellij and error start coming - Can't Resolve Symbols.
Went to Plugins, Updated the plugins & Restart
Problem Solved !!
Related
I'm fairly new to Intellij and Java and am unable to use libraries from one "module" in another. I am seeing red class names and getting "Cannot resolve symbol ..." errors all over the place:
The other modules are referenced in File | Project Structure all the other module's Paths are correct and include the *.classes I'm trying to use:
I have also tried a File | Invalidate Caches but am still having the same problems.
What do I need to do to fix this?
Listed below are steps which may fix the problem:
1.Invalidate and refresh the IntelliJ's caches
File Menu -> Invalidate Caches / Restart -> Invalidate and restart
2.Project SDK selection
Check project settings from File Menu -> Project Structure
Ensure an SDK is selected for the Project SDK. If is selected, click the 'New' button, select JDK and then select the correct path to the JDK e.g. /opt/java/jdk1.8 or c:\Java\Jdk1.8
3.Corrupt JDK
There may be a problem with your JDK installation, re-install JDK
4.Re-import the project
Close the project if it is open in IntelliJ
Delete the .idea folder in the project source code folder.
Start IntelliJ and Import the project.
You can choose any of them which will work for you.
I faced a similar problem for no reason, I think it was caused by IDE(android studio). I have tried all of the above solutions but not worked. Finally, in my own situation, I solved this problem by the following actions:
Delete your .idea folder in your local project.
Reopen this project and just let Gradle run itself.
It was worked for me. I hope that my experience will be useful for you.
You need to add your external libraries/classes under dependencies in order for IDEA to see them when doing code analysis/autocomplete.
You can go to "File->Project Structure"
From "Project Settings", Select "Project" tab and there make sure that "Project SDK" has proper JDK selection.
After you add dependencies to POM file, make it a habit to refresh POM by clicking on the 'Reimports maven projects' icon. Its the first icon in the maven tool window located to the right of the main intellij editor. Its a blue icon with 2 circular arrows. Clicking it ensures that the added dependencies are fully integrated into your project
Run it from the project's root folder.
$ mvn -U idea:idea
One more advise would be to make sure that you import the project properly. If it's a maven project, import pom.xml and if it's a gradle project, import gradle.build file to make sure that all the dependencies are downloaded correctly.
Just got this.
Just went there.
Invalidated the cache.
Seemed to work until I wrote further lines.
Then noticed that I was writing my code outside of the main() function.
Moved the ending curly bracket further and voila.
IntelliJ IDEA 13 has started exhibiting a very weird behavior in my local setup.
Namely, in any new Java class added to an existing project, Code Completion does not work. So, after declaring an object variable of any type in the new class and then typing the name of that variable, followed by the dot (.), no suggestions come up for any of the methods of the corresponding object.
For example, after declaring
File f = new File("/home");
typing f. does not bring up a list of all the methods in the File class, to select one from. As a matter of fact, when typing the dot (.), no suggestions appear and at the bottom left (in the status bar) of the IDE window, the message "Identifier expected. Identifier expected." is displayed. Sometimes, a long list of totally irrelevant methods from irrelevant components or libraries are proposed.
Strangely, Code Completion works as expected if the above declaration happens in any of the existing classes.
This behavior persists after many combinations of machine restart, IDE restart, project re-importing, closing/reopening, or rebuilding.
Any ideas?
Make sure you mark all your Source directories as such in File -> Project Structure -> Modules.
Ensure that you are not in Power Save Mode while running IntelliJ (File [menu] -> Power Save Mode checked or not). If Power Save Mode is enabled, IntelliJ will not run background tasks, including code completion.
For followers, one thing that helped me (auto complete only showed cast
field
instanceof
etc.) was that I had opened a maven module that didn't link correctly to its children (it had a commented out submodules section), so IntelliJ just showed the maven java files as basically "text" files with a tiny "j" in their icon in the project pane. Fixing up the root maven pom.xml file to include the children dirs as modules and voila, they are treated as real java files again, woot!
I am using IntelliJ Ultimate 2017.1, and I encountered similar issue.
Maven project, was trying to using selenium APIs, but the intellisense didn't pop up relative methods for me.
Here is the way I solved my issue:
Right click on your project src folder
Choose Mark Directory As
Then select Sources Root
I had this same problem and it was caused by me not having a folder marked as sources root.
Right click on your src directory and Mark Directory As > Sources Root.
It helped me to mark the src directory as the "Source Root".
Cut the folder .idea and the files *.iml in the root folder and paste somewhere else out of project. when you re-open the project , auto import will work again magically.
There could be 2 reasons for your problem
Either the the source folder is not properly configured in the your build java build path. If the source folder is not properly configured the autocomplete wont get the required class definitions and autocomplete would fail for your project.
Restoring the default options in 'Windows > Preferences > Java > Editor > Content Assist > Advanced'
Right click on project -> Add framework support -> Select Maven -> Click OK
The only thing that worked for me was killing IntelliJ (on Ubuntu) and starting it again.
This is not IntelliJ 13 but a more recent 2017.1.1 Community version. Adding this answer here so that others benefit from a cause that has its roots in the Gradle Configurations.
Now, in my case too the auto complete, Generate Override methods and other features were not working. What I figured out is that in my project settings, I had multiple configurations for the gradle modules. The moment I cleaned up the rest of the modules and retained the only one (apart from test) I needed for that project, all behaviors were back to normal.
Also in such cases of Gradle projects, remember to mark all your sourceSet root folders ad the Source folders.
Edit: If you do not want to create multiple configurations per sourceSet and you are importing a gradle module, on the import screen, you should also disable the Create a module for per sourceSet flag. Without this, I was having to remove the multiple modules after importing the module.
It was happening for me in a module that was not added in the parent project pom (they did it on purpose), that was the reason, I right clicked the pom.xml of the module that has the issue and clicked the
now the autocomplete came and in addition to that I can see the module as a separate project in the maven tab on the top right.
I was facing this issue while coding for eclipse-che client extension. Eclipse che modules are all of maven type. My client extension project was an independent module which can be compiled independent of the parent project. When I imported the same structure to Intellij my client-side extension project was not giving suggestions. After I include the client-extension project to the parent module (adding it to pom.xml) the suggestions started showing up.
Remove your package from the Settings>Editor>General>Auto Import>Java>Exclude from Import and Completion
I had run into this problem. None of the solutions from this post worked, but I was able to fix it because I accidentally put my project's package in the "Exclude from Import and Completion" settings.
I had a groovy project where somehow the jdk was not set as a dependency, so jdk classes would not autocomplete.
Fix:
project structure
modules
(your module)
tab Dependencies.
In the field Module SDK, add a jdk.
I had similar problem, nothing in this topic helped.
So finally I made it work, I clear cache of IntelliJ and restart.
File > Invalidate Caches / Restart.. > Invalidate Cache and Restart (button)
Netbeans is not importing a jar from another project. The classpath is fine, the project compiles fine but the editor show several errors in project because it cannot locate classes inside that jar. I've already rebuilded the projects and clean Netbeans' cache (~/.netbeans/7.1.1/var/cache/)
Netbeans version: 7.1.1 and also 7.0
OS version: MacOS 10.7.3
The problem lies with the Netbeans' code editor. My project compiles and it's packaged just fine. I have no problem on that. I have this annoying error messages (eg. red background) in the code editor with no reason.
A workaround I just found: Renaming the dependency project (with refactoring) and adding the new jar to my project do the trick. Still I don't know what happened.
I just had the same problem in NetBeans 7.2.1 today. I could build the project fine but got error markers in the source files and in the Projects tree listings. It seems as if the compiler when you build a project uses a different classpath from the compiler that works in the edit window.
In my case I found we had the same package and class names for different classes in different jars. I don't know if this is relevant or just a red herring.
I still had an error in one project that used these two jars. It seemed like it could only see the classes from the second jar listed in the pom.xml file (we use Maven). I commented out the second jar & rebuilt, then uncommented that second jar & rebuilt and suddenly all of my errors went away.
So I don't have a definite solution but removing and reintroducing a dependency worked for me.
How you import jar file ? You have to right click Libralies in Project Panel and click Add JAR/Folder. And select jar file which you want to import.
I think you have wrongly imported the jar file. Try out the below steps to add jar(s) to your classpath properly.
1. Select your project from the Projects explorer.
2. Right click -> Properties.
3. Select Libraries from Categories list.
4. Click on Add JAR/Folder button.
5. Add your jar(s) & click on OK to finish the process.
Now, it should resolve the reference issues
You mentioned, the editor shows errors because it cannot locate classes inside that jar. Well, are you sure you are using the right jar or right version of jar ? Eclipse is not able to locate any of the classes or only few classes ?
I wish my answer would help fixing the issue (even if too late :) )
Indeed, I have a maven project with two modules. Module1 that contains the class com.x.y.MyClass and Module2 where I'm trying to import com.x.y.MyClass.
It compiles fine, and I can run unit tests using netbeans, but the errors in the editor were embarrassing. So I add Module1 version and packaging type to the pom.xml of Module2 and that fixed my problem (I know, it's very bad to hard code a module version, but at least, I can work without worrying about the editor list of errors)
Cheers !
This is definitely too little too late, but I had this problem today with Netbeans 7.2. All jars were in place, the code was compiling from the build menu, but Netbeans was marking the files in error.
The same exact project was compiling fine with Netbeans 8.0.1.
The problem was with the "Source Root". I clicked on menu Window -> Debugging -> Sources (Alt+Shift+8) and I noticed that I had specified sources on some of the jar dependencies of the project that were no longer valid. Cleaning them up was a 2 step process:
Clean them up from the project files in nbproject dir
Clean them up from
%APPDATA%\NetBeans\7.2\config\Preferences\org\netbeans\modules\java\j2seplatform\Sources.properties
After clean up, I restarted Netbeans and everything was OK.
Hope this helps someone.
I had this issue with few jsf xhtml pages though there wasn't any error in the content of the page. So I opened each page and cut all content, saved the empty file then paste back all content and saved it. it solved the red marking error symbol for me.
I know this question is a bit old but for those who may be facing the same issue currently, hope this will help.
I faced the same challenge after moving my maven projects to a new directory. To fix the issue, I just simply
Renamed the new folder(the one containing my maven projects) just the same name as the previous folder.
Reimported the projects in Netbeans.
In IntelliJ I get this weird error when I try to compile.
Cannot find annotation method 'cascade()' in type 'javax.persistence.ManyToOne': class file for javax.persistence.ManyToOne not found
I know, it seems pretty obvious what the problem is, but having spent too much time on this problem I now turn my trust to you!
I use ideaCommunity-9, where I have created a global library for JBoss, which contains all JBoss jars including ejb3-persistence.jar. My module includes this library, and I have moved it to the top of dependencies.
No otherwhere in classpath I have a javax.persistence.ManyToOne class, and it also opens up in IntelliJ without problems.
If I open the file where I get the compile error, IntelliJ shows no problems and also navigates to the class file on pressing Ctrl+B.
The code is also build with ant and here it works fine.
Besides the above error I get six others along the same path (name in Table, etc.) - all related to JPA. I also get a message saying "Please file a bug to JDC yada yada yada."
Try to tick a checkbox "export" in your dependencies.
I mean: "File" menu -> Project Structure -> Modules -> Dependencies, and there you can see libs included to the module. You should also see a checkbox near each lib in column 'Export'.
Just got this myself but non of those things were my issue. I downloaded a project from github, then opened in intelli J with the problem after trying to run a junit test.
Solution: Project Structure -> Modules -> 'Project_Name' -> Sources (tab) -> click src folder -> Mark as: Sources
This should highlight src to be blue and all the class files should be the circles with C instead of looking like normal files. Try running a test again and see if that does it.
I'm sure, it is too late to answer, but I had to follow a different approach for this error to resolve this issue.
I had to create this as global library and add that library to the module, then only the error is resolved.
Isn't that similar to this SO question?
The solution there was to add all JBoss jar (which you did), but also all persistent-related libraries (like Hibernate)
See this JBoss project configuration for example:
alt text http://jdick.co.uk/blog/wp-content/uploads/2008/12/projectstructure1.jpg
In short, ejb3-persistence.jar might not be the problem here, just a symptom of other elements missing.
Or, if it is the problem, it may be related to the fact that it is not deployed correctly (for the WebApp configuration).
Here's an idea:
Maybe you have multiple versions of your jar file.
Search your folder hierarchy for the file ejb3-persistence.jar,
using a file management tool such as Total Commander.
Multiple appearances of the file in your classpath may confuse IntelliJ Idea
into not recognizing the proper class in the proper jar.
had a similar problem ("cannot find class spring...DefaultResourceLoader even though it was in my maven dependencies) and no amount of tweaking of revalidating caches seemed to help. Blowing away my $HOME/.Idea* paths and (basically) starting from scratch fixed it for me. At least for now...
I was getting the class not found error message when trying to execute a .groovy test class, which referenced a .groovy file (located in the root of the source directory of a submodule - i.e. no packages).
Moving the source file .groovy into a package, fixed the issue for me.
Move:
src/main/groovy/RunMe.groovy
to
src/main/groovy/somePackage/RunMe.groovy
In intelliJ I got this problem when I built (ctrl+shift+F9) at the file level.
The reason is, I had changes in other files in the same maven project, that were not getting picked.
I solved it by building at the project level (Select the Maven project in intellij and press ctrl+shift+F9)
I'm using Eclipse for Java development. All my sources compile fine and the resulting application compiles fine. However, I keep getting an "red-x" error notification in the Package Explorer.
All my sources in this source directory (too long for the snapshot) compile fine, none of the show the "red-x" error icon.
Any suggestions on how to fix the problem would be highly appreciated.
yeah, this happens sometimes for no apparent reason. You can go to the "Problems"-Tab (right next to console output) and see the error message, so maybe you can narrow it down that way.
This happens often when I use Maven, and I had always ignored it until I found this question. You need to update the project in this case (figured this out by looking in the Problems pane)
From the project context menu: Maven -> Update Project and select the available maven codebases
Alternatively you can use (Alt + F5) to bring up the same window
Try to clean the project and rebuild it.
After build. Refresh project and if still persist just right click Problems tab in eclipse and choose delete all.
It often happens if you do maven install and eclipse properties files do not get updated properly. Even though your project does not have any errors. Hopefully!
I want to start by thanking everyone that answered. But cleaning and rebuilding was not enough in my case because the problem was still there and needed fixing.
Turned out that one of my package directories had accidentally been copied so that an extra directory now existed called "Copy of dagskra" containing Java files with wrong package declarations. In addition the errors in this "new" directory don't show up with a "red-x" in the package that it exists in:
Snapshot from Package Explorer showing errorous "Copy of dagskra" directoryr http://www.freeimagehosting.net/uploads/a824304b18.png
It was the hint of reading the "Problems" tab :-) that turned me into the right direction, so I'm selecting that answer as the accepted answer because this is what I needed:
Snapshot from Problems tab http://www.freeimagehosting.net/uploads/dea26d5dd0.png
Hoping this will help others...
So upon finding that there could be a missing package in the buildpath, thus the red x against the main project, to remove this:
1) go into "Configure Buildpath" of project
2) Java Build Path -> Source Tab - you should see the red x against the missing package/file. if it no longer exists, just "remove" it.
red X begone! :)
Sometimes there are build path errors in .project, and you need to switch to Resource view to actually see the file that is causing the error.
As others have said, bad file references in the build path is often the culprit.
Usually a .jar file that has been moved/deleted. Eclipse expects to find everything referenced on the build path at the location specified, and will complain if not.
I had the same issue and below steps resolved the issue:
Delete the JRE from PROJECT> properties>java build path> libraries.
Restart the eclipse
Add the JRE again
Rebuild the project using Project>Clean and chose option to build automatically.
Please try.
Subversion is occasionally the culprit for this as well. It might not have anything to do with your environment. But, there might be a discrepancy between the current and local state of the project. In my case, doing an update, and then a commit to the subversion server provided me with the expected clean result without any flags in the project such as the X.
In my case what solved this problem was simply to Close Eclipse and opening it again...However I am still not sure why this happened or why it worked. I was having problems Cleaning my project (it said it could not Delete certain file) and this solved it :):
Try doing a rebuild. I've found that the red x's don't always disappear until a rebuild is done.
I've run into a similar problem many a time, what happens usually for me is that a java file will say it won't compile in the text editor but in the package explorer it will say it's compiling fine.
Sometimes doing a 'rebuild' or 'clean-build' doesn't work, the files don't actually get built (one has to presume that eclipse thinks the files it has are up to date) and when this happens I usually open up the java build path and just move one of my dependencies down/up the pecking order. This forces eclipse to do a rebuild of everything and it always seems to work.
If you're still having problems try copying the project and seeing if you get the same behaviour and at a last ditch attempt post a bug for eclipse, it may take a while for them to fix but at least you know that you're being heard.
To add to the previous answer, an extreme way of "cleaning" your project is to delete it (that is deleting its reference from the workspace, not deleting the actual files), and then re-import it.
Sometimes, it helps...
FindBugs also puts a red-x against files/packages to indicate static code analysis errors.
I have run through this. My case was more involved. The project was packaged fine from maven command line.
Couple of things I made.
1. One class has many imports that confused eclipse. Cleaning them fixed part of the problem
2. One case was about a Setter, pressing F3 navigating to that Setter although eclipse complained it is not there. So I simply retyped it and it worked fine (even for all other Setters)
I am still struggling with
Implicit super constructor Item() is undefined for default constructor. Must define an explicit constructor"
I also experience those misterious error-symbols on packages from time to time. A way to get rid of them that works for me is to effectively remove the JRE System Library from Java Build Path and add it back again.
My solution that finally worked was to clean all projects, close eclipse, clean all projects, close eclipse, and so on at least 5-6 times. Eventually it all settled down and everything was as expected. Weirdest thing ever!!
And no there were no errors in the Problem or console view.
Also this happened after a computer crash. The last time it happened my whole workspace was completely lost. It was still there on the computer, but when I tried to access it, it would be all blank.
For whatever reason computer crashes are really really really badly handled by eclipse.
Also, you may update the project by clicking,
Right Click on project name -> Select Maven -> Right click -> Update Project.
This helped out for me.
Thanks.
This can occur for a number of reasons. If you have changed the jdk, the Project facet will have a red X next to it while no other folders shows an error. If this is the case, modify the jdk that is shown. This happens on occasion in our JAX-WS class (HSG
I solved mine by
Close all other projects (i.e. unrelated project option)
Clean and build
My project was android, and that did it.
This happened when i downloaded fabric.io on Eclipse Mars but Restarting computer solved this problem for me.
i had same problem. I checked "Problems"-Tab and found no server for the project. I defined the server. the red-x disappered
You can go to project-> Buildpath-> Library
If there is any library that is X marked ie [cross marked] removed it and again try to build. It worked for me as well/
I encountered this problem today and found this link. I followed as mentioned by Patrick Schaefer above and opened the Update Maven project Dialog. Click on my working project and selected the checkbox "Force Update of Snapshots/Releases" and 'Ok'. All the red cross vanished.
I hope this helps anybody in a similar situation.
The question is old but I had this issue and I tried the following to no avail.
mvn update (with snapshots)
remove project and re-importing
clean build
restarting Eclipse
changing order of items in build path
In my case I've got multi module mvn projects and one of the nested projects was showing a red X icon only in the Project Explorer (package explorer and problems were totally fine) and the whole project was fine as I could run classes without any issues. So seemed like a display issue.
The only thing that worked for me was to edit the pom.xml if the offending project module and make a breaking change (add 'xxx' to a tag name) which caused 1000s of errors and then undo.
You may clean the project by clicking,
In Eclipse, Right Click on Project -> clean
This helped out for me and saved a lot of time.
Thanks.
Right click on the project with errors, then in the sub-menus select:
Maven > UpdateProject >
and then:
Select the checkbox for all the dependent projects
select force update of snapshots
click OK.
This worked for me..