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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 !!
I am having trouble setting up the build path of my java project. I am currently in a Co-Op IT position so I am somewhat new to all this. My background is mostly in C++ and I am learning java on the fly. I am also somewhat new to Eclipse (Kepler service release 1).
I am working on a bug on an existing program and need to get the program to build so I can work on it. When I add all of the external .jar files that I know for a fact are the right ones, I am getting this error on two of them :
"Archive for required library: '(location of file)' cannot be read or is not a valid ZIP file"
Two of the other full time guys on my team have gotten the program to run with those exact same .jar files, one running Eclipse Indigo and the other running the same Kepler version as myself. I also was able to open the two .jar files manually and everything appears to be there. After every trial trying to fix this, I have refreshed, cleaned and restarted eclipse. The two other full time guys said they have never seen this error. I would like to get some insight on this from anyone who has any similar experiences so that I don't have to use up much more of their time.
I Had this issue, just fixed by deleting .jar files from Libs directory then copy->paste original Jars again. Then do a complete clean -> rebuild
I got this problem, took help from following link solution
which basically says to
1. delete the corresponding maven download folder
2. maven>update project in eclipse
In my case I deleted hibernate folder, since i was getting error related to hibernate-validator.jar
I had the same error here. What I did to resolve the problem was close and reopen the project.
I got the same problem and found out the root cause is the JDK in my linux shell is set to 1.6, but in the eclipse, the JRE is 1.7.
Using Eclipse without m2e features (Standard Edition) helped me.
Similar problem with Spring toolsuite
Just came across this link that shows a way to get unblocked.
In preferences dialog box go to
Java->Compiler->Building
and change Incomplete build path to "Warning" (from default "Error")
This can be done globally (for all projects), or on a project by project basis.
Check the jar's file permissions/ownership.
I had the same issue on eclipse installed on Linux and fixed it by setting the file permissions right.
In my case ..worked after removing this from spirngrest-servlet.xml file.
<prop key="net.sf.ehcache.configurationResourceName">/Sysehcache.xml</prop>
I think it had to do with default location of maven repository of jar files.
Been at it for 3 days. finally solved it.Hope it helps anyone.Just look for similar think in your spirngrest-servlet.xml file. Good luck.
I just tried the following and it worked:
Close eclipse as there might be some files eclipse is accessing and you won't be able to delete.
Delete all the libraries installed in the maven repositories folder: ".m2/repository"
Open eclipse and update your project(Alt+F5).
What did we just do? : This is possible that the existing libraries in the local repository are erroneous and maven tries to open which it fails in. We have now deleted the already existing library and with the project update, Maven will download the library again which should resolve the issue.
i fixed this by just deleting everything inside of the /Users/username/.m2/repository folder. not the repository folder itself. and then running a mvn clean package in the project folder
I'm on Eclipse for hours now and I didn't found a solution yet for my problem even after many searches on internet: I have no more R.java file on my projects.
On just created or on my old projects, i don't have R file anymore and I tried so many solutions (uninstall, re-install Eclipse, clean my project, check all my XMLs, fix problem with android tool and so on ...)
Please someone can tell me what to do in this case?
Hey If you just updated to ADT Rev 22 :
I had the problem too. There is a new component in the Tools folder called "Android SDK Build-tools" that needs to be installed.
Step 1
Open the Android SDK Manager
Step 2
Select the newly added Build Tools and install. (If problem stays then go to Project Properties => Java Build Path => Order and Export and check Android Private Libraries, then clean and build project.
It may be necessary to repeat the process, restart the SDK Manager after the update and make sure it looks like this (all tools installed):
More info:https://groups.google.com/forum/?fromgroups=#!topic/android-developers/rCaeT3qckoE%5B1-25-false%5D
Perhaps in Project Properties -> Java Build Path -> Libraries you don't have:
Android 4.2.2 (or other version)
Android Dependencies ?
If so, then right click project - > Android tools -> fix android properties
and see if this library showed up.
Thank you all for saving me! I've spent the whole afternoon on search this error.
Finally, my project works.
By the way, I also encountered one problem which i wanna share with you:
After upgrading, even if my project has not errors anymore. During runtime, it seems it couldn't find the classes from the jars placed in \libs.
Go into Project=>properties => Java build path= > Order and Export.
Please make sure all your jars are checked.
If this problem occurs suddenly in a well working project,
the first step is to find whether the problem occurs only in the current project or in all other projects.
if all other projects in the current workspace are working then 90% problem is with XML / mainfestfile/resourse file that you edited recently.
This error is not shown as red mark we have to find out what we have done recently in these files.
try this
sudo apt-get install lib32stdc++6 lib32z1 lib32z1-dev
it solved my problem
Close your eclipse and after refreshing system, try to open Eclipse again. I think you are using Emulator along with the eclipse. It may be because of the low Memory problem (RAM) of your system. I used to face the same problem when I use Emulator
whenever there is any mistakes in any of the xmls the R goes missing when a build or clean happens so check for any xml errors in your project unless you fix it you cant get back your R on clean or build. fix the xml files and perform a clean you will have the R generated. Also check in File->properties->Builders and see if everything is checked
I was using Eclipse Indigo and nothing I tried worked. I ended up downloading Juno SR2, reinstalling the ADT, and now everything works again.
Reinstall everything and it'll work.. i.e. go back to Google SDK or w.e. you're using and download it.
Update it to latest in SDK Manager.
Go into Eclipse-Project-Prefs-Java build path-order/export TICK EVERYTHING.
problem: No R file get generated.
guess: Try cleaning project if it is old one. Else create new project with no R get generated and with no compile errors but this: no project.apk
In this case you have to check your SDK for the built-tools. May not be installed after updating SDK.
Thus download them if not download here, then put them under directory: SDK/built-tools folder. Lastly, and most important, is to Run the SDK As Administrator. This guarantees refreshing SDK with all packages appearing in it.
Install the SDK-Built-Tools or any missing packages according to the above link and you're done.
hope this helps.
Try one thing, create a new Android Project and transfer all those files which are in the previous project. That worked for me.
In my case there is error due to "&" inside strings.xml file(but error not shown) for declaring string for a array type. Now the problem has been solved as I changed "&" to "and".
So, please make sure that you do not have such silly use of symbols, and clean the project.
I have had the same kind of problem, however Rechecking all XML files in the Resources folder was helpful in my case. I found syntax error in my XML files. Cleaning and building the project again can be helpful sometimes too.
I had the dreaded not more R.java.
Some of the things I've used in the past:
Clean / rebuild (the first thing we all try)
Restart eclipse (optionally reboot pc/mac)
Update both SDK/ADT eclipse plugin to latest version
Create new eclipse workspace and import project
Enable Verbose AAPT build output Eclipse menu>Preferences>Android>Build
Port project to Android Studio / Gradle (this helped my actually see the AAPT error i was getting Error Code:138)
Delete recent XML changes - Ultimately I found deleting recent menu.xml files I'd added and commenting out where they were referenced fixed the issue and I finally got R.java.
I got the error recently and had found no fault in any layout or value file. After a lot of tries I add another Activity and the R.java was build and the error disappeared. I don't know why this occur, but it takes me hours.
I downloaded the sample Restlet project and opened it in Eclipse. I instantly get this error:
Errors occurred during the build.
Errors running builder 'Google WebApp Project Validator' on project 'org.restlet.example.serialization.gae-gwt'.
java.lang.NullPointerException
What am I doing wrong?
I had this same error with my own project. In the Eclipse Project Explorer I right-clicked the project and chose Refresh. That cleared up the error for me.
This is a temporary, but repeatable solution someone on my team found...
Close project
Close Eclipse
Open Eclipse
Open project
I continually had this problem in combination with git. My git repository was in my eclipse workspace ( even though eclipse warns you not to do this ). Deleting the old repository, and creating a new git repository outside of the eclipse workspace, then cloning a fresh copy of my gwt project solved this problem for me. Hope this helps.
I'm also experiencing this error, but thanks to git comparing .classpath I noticed that I had removed a couple of variables from the "Configure Variables" list, but not from the Java Build Path. Once I removed it from the second list, the error was gone.
I got this error when I was using a workspace that was on an NFS and I had the same workspace open on two different vnc sessions. I closed out Eclipse on one vnc session and then restarted eclipse on the other. Then I went to the java build path and editted the gwt sdk and had it use the gwt sdk it was already pointed to and it stopped giving me that error. I didn't actually change the gwt sdk, just went through the motions of doing so. Hope this helps.
The problem was miss configuration of JRE, I just did the following:
Go to Build path configuration, select add Library, JRE System Library, select your JRE.
And there you go...
For me this error seemed to occur after a compile had failed due to lack of memory and eclipse had been restarted. However, after increasing memory (in the eclipse.ini) the problem still persisted. None of the above solutions worked for me.
The bizarre solution I found: our project here uses GWT 2.4, so I switched to 2.5 (which comes with the plugin - window>preferences>google>Web Tookit), re-compiled, switched back to 2.4 and, hey presto, it worked again!
(Another hour of my life I'll never get back!)
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..