Eclipse: The project was not built since the source file ... could not be read - eclipse

When compiling my Java project, I get this error in Other errors:
Description Resource Path Location Type
The project was not built since the source file /PROJECT/src/main/org/../ABC.java could not be read PROJECT Unknown Java Problem
Indeed, the file is listed in Package Explorer but shows only "Error retrieving content description. On the file system, the silent dir exists but not the file; git status is missing nothing. How do I resolve that compile error?

Simply restart eclipse, refresh all projects and do a clean build. That should fix it. Don't forget the eclipse restart, else no matter how many times you do a clean build or refresh, it will not fix the problem

Looks like someone has deleted that file but eclipse still think that file is part of the project. Might have happened when someone deleted a file from the source control in an improper way.
If you dont have pending changes then you can get fresh copy of the project and import it into your workspace.
If you have pending changes then take a copy of changes and repeat above step. ( A restart of eclipse may be necessary)

It can be related to missing location
Select File => properties => Resource => Edit file location.

I know the answer is accepted but in my case that solution didn't work for me, I had restored files from a backup to my local project in linux and the files I restored were owned by root with only the owner being able to read/write the files. SO, I sudo chowned the files "sudo chown _R myUser:myUser *" at the base of my project, refreshed in Eclipse (f5) and the annoying repeated failure of my build was a thing of the past.

If you are writing Maven projects, try right click on the project and select [Maven] -> [Update Project...]
It works for me.

For me there was a different solution than mentioned here.
I was doing a no-no, I imported a project that had a .project file, and there was some errors in the way my version of eclipse was reading some of the files. The package names and files had a little ! symbol with a yellow background.
The solution was to delete the packages. Obviously make a backup. But in doing this most times the files nor the packages were deleted. Instead eclipse refreshed and the desired files were there. Sometimes I had to hit refresh (F5), and sometimes I had to restore files.
I found it best to delete the packages as that is where eclipse was having reading the data.

If the missing file is still mentioned in the Linked Resources, no refresh and restart of Eclipse will ever solve the problem. You have to delete the file in the Project Properties Linked Resources list.

For anyone using VS Code with the RedHat Java plugins (which use Eclipse tooling under the hood), I got this error as well. I fixed with the following:
# Quit VS Code
rm -rf ~/Library/Application\ Support/Code/User/workspaceStorage/*
# Reopen VS Code

As all others said, it is most probably an issue with the internal caches of Eclipse.
I usually restart the IDE with the additional -clean option to wipe out the OSGi-related caches, then clean and rebuild all the projects.
If the problem persists, I realized that cleaning up the single affecting project works better that cleaning up the whole workspace. (Ominous... XD)
This usually happens to me when merging changes that imply renaming or deletion of source files, prior to launching Eclipse.

Related

An internal error occurred during: "Updating Maven Project". Preference node "org.eclipse.wst.validation" has been removed

I'm trying to open my Maven project with Eclipse Juno, but I'm getting this error:
An internal error occurred during: "Updating Maven Project".
Preference node "org.eclipse.wst.validation" has been removed.
How is this caused and how can I solve it?
Same probleme here, there the solution I fix it
Open the .project file with your prefered text editor.
delete the node that is about "org.eclipse.wst.validation"
Close your project
Open your project
Launch Maven Update...
Should be good.
Another way to fix it, if you don't want to change your .project config
(or if you had several projects that must be fixed)
Close your workspace (or eclipse)
-move out <WorkspaceDir>\.metadata\.plugins\org.eclipse.core.resources\.projects from the workspace directory
-reopen you workspace
close it again
-move back the .projects dir (say yes to replace questions ? )
open you workspace
Launch Maven Update
Should be good
Simpler fix:
Close Project
Open Project
Project > Clean
Run Maven Update
I was using Eclipse Mars and in my case, just close and reopen my IDE did the work.
Dont know, if you still have this problem, but here is the solution worked for me:
It appears that deleting the file org.eclipse.wst.validation.prefs in
the directory .metadata/.plugins/org.eclipse.core.runtime/.settings
(default settings for workspace) or .settings in each individual
project will cause the settings for validation to be reset to their
original settings. You can then use validation without getting error
messages and try resetting the options from there. However, I'm not
sure what combination of settings would cause the problem to reappear.
However, if it does, you can repeat the process.
got this from here: https://bugs.eclipse.org/bugs/show_bug.cgi?id=355012
in my case i didnt have the mentioned file in this folder, but i had a bunch of other org.eclipse.wst.* files. deleting them all did the trick for me.
The problem is not related to the .projects folder as mentioned in another answer.
The solution is to add a file called org.eclipse.wst.validation.prefs in the .settings folder. This will restore the eclipse validation node.
The content of the file, depending on your eclipse version, might look like this:
disabled=06target
eclipse.preferences.version=1
Another Solution is too simple , deleting .project file then clean the project and maven update will success surely
I think this is one error that could be caused by multiple different sources. I just had the same error however, and just figured out why. In my situation, I just tried to force update some code by deleting a few temporary files. Turned out I accidentally deleted that file as well. I thankfully had it under source control, so I pulled the file back and updated the project with Maven. I also made sure any other errors were fixed so that the project would clean / update successfully.
I'm not sure if this will solve your problem, but I hope it helps! Good luck!

Eclipse: "'Periodic workspace save.' has encountered a pro‍blem."

I'm using Eclipse Indigo on Mac 10.7.4. While working, I get these periodic, annoying dialogs
'Periodic workspace save.' has encountered a problem.
Could not write metadata for '/.org.eclipse.jdt.core.external.folders'.
/Users/davea/Dropbox/workspace/.metadata/.plugins/org.eclipse.core.resources/.projects/.org.eclipse.jdt.core.external.folders/.markers.snap (No such file or directory)
I seem to be able to continue as normal, but I was wondering how I can eliminate these errors.
I had the same problem.
'Periodic workspace save.' has encountered a problem.
Could not write metadata for '/External Files'. D:\java\fuentes\.metadata\.plugins\org.eclipse.core.resources\.projects\External
Files\.markers.snap (El sistema no puede hallar la ruta especificada)
I created the folder "External Files" and it worked fine. In a few minutes the files ".markers.snap" and ".syncinfo.snap" appeared in this folder and the message didn´t appear any more.
I fixed mine by closing eclipse and deleting the whole .metadata folder inside my workspace folder.
Today I faced the same issue consistently, whenever I exit the eclipse.
While trying the above solution provided by TS.xy, the below steps got rid of this issue for now.
Switch to new workspace and close the Eclipse.
Open the Eclipse with new workspace and after that switch to the actual workspace(in which
exception occurs).
Actual workspace loaded with all my previous projects.
Now exiting the Eclipse, does not result in that exception.
Hope that this step may work for someone.
Just for another data point, none of the above helped my situation. The way I finally got past this issue is that each time Eclipse complained about some folder not being there, I went on my hard drive and created the folder. E.g. after I see
Could not write metadata for '/servers'.
C:\...\.metadata\.plugins\org.eclipse.core.resources\.projects\servers\.markers.snap (The system cannot find the path specified.)
I create the "servers" folder (not the file inside it). This gets me to the next error. I went through 3-4 of these iterations (exiting Eclipse each time to force the save) before the issues went away.
HTH, Mark
This was simple for me -
Solution
(pre) the listed directory is not present, see pic
Run Eclipse, see the error shown in pic below. Close Eclipse
Create the directory (RemoteSystemsTempFiles) where it is looking
note: ignore the items in this folder (e.g. .markers), they are auto-generated
Restart Eclipse, problem solved!
Example Problem Message
Not sure why this took me so long to resolve, but quite easy now, and quite obvious in retrospect! ;)...
Using Ubuntu, got the same issue
I noticed that the owner of some of the directories in
~/workspace/.metadata/.plugins/ ...etc...
was root
changed owner to me and the error stopped happening.
Looks like the same sort of issue may be caused by multiple causes.
Close the Eclipse , Clear the .metadata folder completely.. Start Eclipse & Import the necessary project once again if your project references are deleted..
The solution that work for me is the following:
Delete .metadata folder
Restart eclipse
Solved it by setting workspace on a local folder, and set data from import project, from existing resources.
I encountered the same problem , my resolution was to rename the the folder name under the workspace folder. i.e. com.ibm.collaboration.realtime.alertmanager.embedded was renamed to com.ibm.collaboration.realtime.alertmanager.2embeddedxx and rebuilt my project.
In my case, because I've accidentally deleted my workspace folder, and I observed the 'Periodic workspace save has encountered a problem". To solve this issue, I just simply create a new workspace and load all my projects to the new one. Hope you can solve your problem by doing the same thing.
I also ran into this problem. My situation was a little different. I was using 'working sets' to group my projects inside of eclipse. What I had done was attempt to delete a project and received errors while deleting. Ignoring the errors I removed the project from my working set and thus didn't see that I even had the project anymore. When I received my error I didn't think to look through my package explorer with 'projects', opposed to working sets, as my top view. After switching to a top level view of projects I found the project that was half deleted and was able to delete its contents from both my workspace and the hard drive.
I haven't had the error since.
I had gotten a little too aggressive about removing some directories in my project area when I was running out of disk space, and deleted this directory. Eclipse can leave some huge core files if it crashes in your workspace directories, (I had 35 gig of them) so it's worth taking a look there in your workspaces occasionally.
Anyway, as per the problem I tried the 'create a directory' approach. And it worked.
I was also seeing this error when I closed Eclipse by the way, not only after the 'periodic save'. So the exit/restart was also part of this.
Note that the last item on the directory path specified in the error message is a file -- not a directory, so don't get confused here. Probably worth checking that the directory permissions are created correctly as well (as the other projects in the workspace I think).
Obviously this is a bug in the Eclipse code base, (creating the full directory path under the file that is being created), but had I not deleted it in the first place, I would not have caused it in the first place.
I have the same problem since yesterday. Yesterday, I fixed it by creating a new workspace and reimporting the projects. It seemed to work well, but today it started again.
So, today I created the folder and the file manually and gave the full permissions -rwxrwxrwx.
Seems to work again...
Close Eclipse. Open RemoteSystemsTempFiles folder in Workspace, and clear inside this folder. Again open eclipse and close, warn about .project. Press Ok, then open Eclipse.
Solved my problem that.
I ran into this problem today after they switched our anti-virus software to Kaspersky.
In my case, the platform is Windows 7. My workspace is stored on mapped network drive. The strange thing is that, even though this appears to be a permission issue, I could manipulate files and folders at the same level as the inaccessible file without incident. So far, the only two workarounds are to move the workspace to the local drive or to uninstall Kaspersky. Removing and re-installing Kaspersky without the firewall feature did not do the trick.
I will update this answer if and when we find a more accommodating solution, though I expect that will involve adjusting the anti-virus software, not Eclipse.
In my case, the drive I was storing my workspace on had become full downloading SDK updates full and I just needed to clear some space on it.
This happened to me because i deleted one of the resources files inside the .metadata folder in my workspace.
After trying all methods, deleting the .metadata folder in my workspace worked.
Infact, this nuke option seems to work when there are a lot of issues related to eclipse bugs. One such example is working-sets. Working-sets are extremely buggy(but useful) and it is there that most of my eclipse problems start.
Hope this helps someone.
I solved the problem switching the workspace.
Go to File (Switch workspace)
Select the destination and create a folder named Workspace
Run a Hello World and close Eclipse (notice that Eclipse creates the folder RemoteSystemsTempFiles automatically)
now copy all your projects into the new folder Workspace
Open Eclipse and if necessary (sometimes Eclipse does not show the projects) import all of them (go to File/ Open projects from File System)
After you exit the eclipse, there would be an specific failed reason.
Mine is that the DISK IS FULL so the eclipse can't write into it anymore.
Agree with #J-Dizzle,
I am a beginner in web-development and had a hard time solving this today.
Had similar problems when I was creating a SpringBoot project in STS.
Tried most of the solutions mentioned but they didn't work.
Tried removing .metadata folder and re-building my springboot project but still nothing worked.
NOTE : I had multiple workspace in STS and this error occurred after migrating a project from one workspace to another.
Solution : All you need to do is restart your eclipse/STS IDE and it will work just fine.

Eclipse IDE does not start

My computer suddenly shut down due to power failure, while I was working on an Android project using my Eclipse Indigo IDE.
Now, if I start Eclipse, only an empty message dialog (see screen shot) appears and Eclipse does not start. What can I do?
(I am using Ubuntu 12.04 LTS)
Mabe Some files found in the .metadata folder of your workspace are damaged, have you tried to launch it by specifying another workspace?
You can manually specify the workspace location on the command line, using the -data command-line argument.
If you don't want to loose a lot of time by trying to fix the problem, you can import your projects into the new workspace, reinstall the plugins that was installed before and everything will be ok. otherwise, you have to take a look on the .log file found in the .metadata folder of your old workspace, analyse the stacktrace and try to understand which plugin is corrupted and delete it manually, and this may take a lot of time, thats why i suggest you the first solution. About the .metadata folder, it is in ~old_workspace/.metadata.
check your filesystems. Maybe something got corrupted when power was lost.
Check my blog post When Eclipse Won't Start and Restoring a Corrupted Workspace in Eclipse
For me, .metadata files were damaged. Since eclipse was not opening at all, changing the workspace was not an option. I deleted following directories, and could start afresh!
.metadata
.buildpath
.project
Hope this helps you as well.
Please note that you will end up loosing all the project settings.
I know my reply is too late. Hope this helps another user.
My Ubuntu in the VMware was shutdown abnormally for some reason. When I logged back in Eclipse would not start. I fixed with the following steps:
removed .lock file in the .metadata folder in the workspace
started eclipse using command line with "-clean" argument
It started fine!!!
I tried to find the corrupted file by removing the files from ~/workspace/.metadata/ one by one until Eclipse could start.
The corrupted file was ~/workspace/.metadata/.plugins/org.eclipse.core.resources/.snap
Once the file was removed Eclipse started normally.

Subclipse complains "Path is not a working copy" after moving workspace

I recently moved my Eclipse workspace directory and now Subclipse complains every time I open a file, dumping to the console something like:
Path is not a working copy directory
svn: '[original (pre-move) directory path]' is not a working copy
No such file or directory
This also happens when I explicitly try to view the history of a file. This persists across SVN cleanups, closing and re-opening Eclipse, etc.
Update, checkin, checkout and so on all seem to work fine, and Tortoise doesn't complain at all, so clearly it's not the SVN metadata that's screwed up, it's some Subclipse-specific metadata. Can anyone tell me how to blow this broken metadata away?
Edited to add: "Team > Disconnect" followed by "Team > Share" doesn't solve the problem.
Edited again to add: I've grepped through the whole .metadata directory and one of the project directories for a unique element of the old path and can't find it anywhere except in .metadata/.log (the error message itself) and some old Findbugs warnings. Very nice.
You need to delete the .syncinfo files. This is easily done (in most cases) by closing and opening Eclipse, however you can also do so manually as in the following:
To delete the cache, close Eclipse. The cache is stored in:
[workspace]/.metadat​a/.plugins/org.eclip​se.core.resources/.p​rojects/PROJECTNAME/​.syncinfo
So you can just find and delete all files named .syncinfo in
[workspace]/.metadat​a/.plugins/org.eclip​se.core.resources/.p​rojects
Quoted from this article: http://subclipse.tigris.org/ds/viewMessage.do?dsForumId=1047&dsMessageId=868799
I just did a "Team -> Cleanup" and this exact error went away! I also got this error because I moved between machines and the path wasn't the same.
Using Eclipse 3.6 and the Subversion 1.6 plugin.
Update in 2016: Still works perfectly with Eclipse 4.5.2 and Subclipse 1.10.
Edited to add: Nope, spoke too soon. This doesn't fix it. Some files just seem not to exhibit the problem.
The following seems to solve the problem:
Team > Disconnect.
Quit Eclipse.
Blow away .metadata/.plugins/org.tigris.subversion.subclipse.*.
Restart Eclipse.
Team > Share.
Not sure how the old path was actually being stored in the plugin prefs, but it must have been in there somehwere. It's kind of pathetic of Subclipse to store absolute paths, but apparently it is.
There's a bug filed on this, or at least on the same error message. No context. Fifty cents says it gets rejected.
I'm sure there are many causes with different solutions, but I found the one that worked for me at Dan Wilson's blog. Simply remove the offending folders from the workspace (probably saving them if they have new content), update (letting Subversion recreate the folders), then move the contents back into the fresh folders in your workspace.
I got the error when I tried to rename a class by changing the case from DAO to Dao in Eclipse.
I had to rename it to something like Dao2 and then was able to rename it to Dao.
What worked for me:
Do a "refactor - rename" on the project => after that do it again to rename it back to the original name.
I was having the same error message using subclipse with javahl on a project that is out of the workspace directory. Changing to svnKit has resolved my problem.
Hard to say without further information.
Did you move the whole workspace or just the content?
Also, you can try creating new workspace from scratch and check out the whole project again.
Alternatively, you may try deleting the .metadata directory and relink the project again using File -> import -> existing project into workspace and then relink the SVN data through Team -> Share projects (with an 's'), or maybe just do this last bit after first disconnecting the project from SVN.
Right click the project folder : Team -> Update to Head
This will bring back the directory. Delete it again and Commit
In my case I had the folders of the projects in the Project Explorer and just had to reopen the project
For me, this error message was caused by an out-of-date installation of Subclipse, and the underlying SVNKit and JahaHL libraries. I have been using TortoiseSVN outside of Eclipse to manage my project directories, and my recent upgrade to the 1.8.x series of (Tortoise)SVN tools broke my working copies for Subclipse.
All I had to do to fix, was go to Help->"Install New Software..." and click "Add..." to add a new update site. I picked the latest update site for the latest release on http://subclipse.tigris.org/servlets/ProjectProcess?pageID=p4wYuA and upgraded Subclipse from there.
Then all my existing projects just worked, and I could reconnect to the one I had already tried disconnecting from without problems.
I have the same problem
I had a new project, added it to SVN. Then everything works as normal, until I try and refactor-rename any java file, I get:
move D:/dev/sk_ws/ge-parent/ge-core/src/main/java/com/skillkash/ge/beans/Skbean.java D:/dev/sk_ws/ge-parent/ge-core/src/main/java/com/skillkash/ge/beans/SkBean.java
Path is not a working copy directory
svn: Path 'D:\dev\sk_ws\ge-parent\ge-core\src\main\java\com\skillkash\ge\beans\SkBean.java' is not a directory
Now the SVN URL is:
svn://qnap/share/MD0_DATA/svn/sk/ge-core/trunk
and the repository root is:
svn://qnap/share/MD0_DATA/svn/sk
Obviously just sharing the project then trying to move a file using subclipe does not work - it must be a bug. I have to do all my refactoring outside eclipse, and hand edit all the files which are affected.
checkout the whole project to a temp dir, then I copied the first level .svn directory and replaced my working copy .svn folder with this.
http://blog.itopia.de/directory-svn-containing-working-copy-admin-area-is-missing/275
It woks for me.
I had added a png file to my project, but I got this error trying to rename or delete it. Cleaning and refreshing the project didn't do anything.
I went into the svn Team Synchronizing perspective, right clicked on the file and deleted it. That solved my problem.
Right click on the project and select Teams -> Switch to another Branch/Tag/Revision.
Select the appropriate Branch/Tag/Revision that the project should be tied to and click OK.
Give Eclipse some time to process the changes.
Restart Eclipse for the changes to take affect.
I just got this error when I was trying to update some .java files. The problem was I was trying to update the files but the folder that contains that files didn't exist in the path so when I sync and update the folder it works at the first try.
So, dont try to sync files, try to sync the folder.
Sometime ago I had a similar issue. Seems that Subclipse (or Eclipse) stores the absolute path of your working copies. The cleanest solution is to export again your repository to the new path.
If you have non-committed code, then you can copy it on top of the clean export (without the .svn folder)
I too had this issue and I simply deleted the project from the workspace (leaving the files on the files system in tact).
I then imported an svn project into the workspace.
Import->SVN->Checkout Project From SVN.
I used my existing repository location to pull the files in.
This issue was caused when I changed Eclipse editions and used a Subclipse plug-in that was a version ahead of what I should have used.
I uninstalled the newer version and installed the correct older version and all worked well.

eclipse stuck when building workspace

I am using eclipse 3.4.1 Java EE under Vista. It seems to like getting stuck when building my workspace. Canceling the build doesn't seem to do anything as well.
Why is this happening and how do I fix the problem?
I was able to fix this with the following:
First, exit Eclipse. Then temporarily move the following .projects folder to a safe location:
mv .metadata\.plugins\org.eclipse.core.resources\.projects projects
Start and exit Eclipse, then move the .projects folder back to where it was originally:
mv projects .metadata\.plugins\org.eclipse.core.resources\.projects
Use at your own risk, of course.
Some time it's very helpful to execute eclipse from command line with "-clean" parameter to enforce it produce clean up for workspace.
eclipse -clean did not work but following did
eclipse -clean -clearPersistedState
Eclipse often freezes for me at 44% if I'm debugging Android over USB.
When disconnecting the device, Eclipse starts.
The accepted answer allowed me to get Eclipse started again, but it seems that the projects lost their metadata. (E.g., all the Git/Gradle/Spring icons disappeared from the project names.) I have a lot of projects in there, and I didn't want to have to import them all over again.
So here's what worked for me under Kepler. YMMV but I wanted to record this just in case it helps somebody.
Step 1. Temporarily move the .projects file out of the way:
$ cd .metadata/.plugins/org.eclipse.core.resources
$ mv .projects .projects.bak
Step 2. Then start Eclipse. The metadata will be missing, but at least Eclipse starts without getting stuck.
Step 3. Close Eclipse.
Step 4. Revert the .projects.bak file to its original name:
$ mv .projects.bak .projects
Step 5. Restart Eclipse. It may build some stuff, but this time it should get through. (At least it did for me.)
Step1:
Open project directory and edit .project file, remove following lines to disable java script validation.
<buildCommand>
<name>org.eclipse.wst.jsdt.core.javascriptValidator</name>
<arguments>
</arguments>
</buildCommand>
Save file.
Step 2:
Go to Eclipse installed directory and open eclipse.ini(or sts.in if you have STS), change xms and xmx value based on your RAM size of your computer.
-Xms512m
-Xmx1024m
-XX:MaxPermSize=256m
OR: in windows, go to eclipse shortcut in desktop, right click->properties-> add following:
C:\software\eclipse\sts-3.6.2.RELEASE\STS.exe -clean -Xms512m -Xmx1024m
Run Eclipse.
Go to Eclipse->windows->preference->Validation, enable Suspend all validators. Do this if you don't want do any validation listed in the list given in Validator panel.
I have this problem whe I have too much maven projects open at once. What I tend to do is:
Restart eclipse (sometimes I need to kill eclipse)
Disable automatic build immediatly (project > uncheck Build automatically)
Right click the project(s) I want to have rebuild
Close unrelated projects
Re-enable automatic build
This enables a functioning rebuild in 99% off the cases in my workspace.
You may want to take a look at How to report a deadlock. You may also want to check the Error view and/or the error log ([workspace]/.metadata/.log). If that doesn't help, you'll probably need to include more info about which plugins you have installed and which projects you have. Can you create a minimal workspace which reproduces the problem?
I faced Similar issue in Eclipse Indigo. I changed the HeapSize it started working correctly. I just added following eclipse.ini file
-vmargs
-Xms1024m
-Xmx1024m
It worked fine after increasing the VM size
The only solution for me (Luna 4.4.1) was this:
Go to Project Properties > Builders and then uncheck the Javascript Validator.
I had same issue with my Eclipse and as a solution, I created new project, copied all resources manually (using windows copy/paste) to new project, deleted old project and that's it.
Sometimes, this happens due to improper System shutdown and Eclipse workspace started facing similar issues.
Hope it will work.
Unselect automatic build using Eclipse-> Windows->Preferences helps fixing this issue.
Deleting some of the JDT indexes (in .metadata.plugins\org.eclipse.jdt.core), particularly the big files, often fix or ease the problem for me.
I just had the same problem.
By using Task Manager to kill the build process and exiting Eclipse with no projects open, I was able to get back into Eclipse and clean the project without opening it. I then restarted Eclipse again,loaded my project and all OK.
I've found that this might also happen if you rebuild a workspace with a project containing a lot of image data (such as a dedicated images project). Might be best to put something like that into its own workspace and handle it separately to the rest of the projects you deal with.
If you can't, then don't clean that project when you clean and rebuild. Only rebuild when necessary.
In my case problem arise after importing downloaded project - stuck at 80% build. Solved by adding write permissions for group to project's files (Ubuntu 12.04).
In my case it helped to remove the source folders from my favorites in the Windows Explorer (Windows 8.0). It seems that the build was not actually stuck, but triggered in some kind of infinite loop (as mentioned here - Bug 342931).
Sometimes the problem seems to be fixed by killing other programs which have files open from the project folder.
Looking at the logs in [workspace]/.metadata/.log provided useful information for me.
Turned out there was a java.lang.OutOfMemoryError: PermGen space error when the workspace build would hang.
This can be edited in the eclipse.ini or sts.ini(If you are using SpringSource Tool Suite) file.
I faced the same problem when I tried to install Angular.js with bower in my project. I seems bower has lots of javascript files it downloaded automatically which caused my IDE to stuck in validation process for a long time. So, I solved this problem this way,
I first installed tern.js 0.9.0.
Then I went to the project properties, selected tern script path
included only the path I needed for validation, My project's
javascript folder. I excluded other path like placeholders,
Angular.js files, Jquery files.
I selected the Javascript from the properties again and did the same
things in include path's source.
My IDE currently working without freezing. I took help from there. Tern
I guess it can be helpful, where any IDE stuck due to lots of Javascript file.
I tried lots of these suggestions, but the only thing that finally worked for me was creating a new workspace, and freshly checking out all my projects into that folder. Then it worked fine ;-)
I just restarted eclipse and it started working the next time.
Refresh all the projects u want to build.
Worked
Restart eclipse.
It worked for me several times.
I was able to solve this by removing extra folder that Eclipse had created in my eclipse installation folder. I didn't install and I was using Eclilpse Neon 3 with Spring Tool suite also installed. But, when I looked into extracted eclipse installation, I had C: folder which had some folder structure. It was mirror image of my Downloads folder. I removed it and restarted.
It worked for me!
None of the the answers here worked for me. What worked was to delete the following folder
C:\Users\your username\workspace\project
name.metadata.plugins\org.eclipse.core.resources.projects\project
name\.indexes
Rather than debug and find the exact root cause(s) for this, I just deleted the projects and the metadata folder. Eclipse will rebuild the .metadata file the next time it's launched.
I then pulled in the latest project code and the problem was solved. It was more work as I had to reconfigure everything, including my servers, but build workspace had been stopping at 50% for anywhere from 3 to 5 minutes before it would completely finish, so it was worth the effort.
Also, I've found that with Eclipse, if you stop the build workspace before it completes and shut down Eclipse if that hangs up everything, you can really mess up your configuration and waste lots of time trying to get it stable again. I'm using Eclipse Oxygen, but I've had this happen in all the versions of Eclipse I've used, so I really try to avoid it, if possible.
Inside the project folder open .project file. There is a bad entry and it might help
<buildCommand>
<name>org.eclipse.m2e.core.maven2Builder</name>
<arguments>
</arguments>
</buildCommand>
If you are using Maven as a build tool you might want to:
Close eclipse
Delete dependency directories located in .m2/repository/ - in
Linux
it's located under Home directory and in Windows it should be in c:\Users<YourUsername>.m2 (replace '' with your
username)
Start Eclipse and enjoy normal work :)
That helped me resolve this issue and I hope it helps you too. :)
Cheers!
P.S. I've edited my answer (as #howlger asked) where it was also suggested to delete .eclipse and .p2 folders as it can do harm (although it did NOT in my case + I had to reinstall some of plugins I'm using).
In case there is a problem on start when building your project disable the build automatically from menu. Project -> Build Automatically. This solved my problem while more sophisticated solutions could not.