Eclipse Build Error "A class file was not written. The project may be inconsistent, if so try refreshing this project and building it"

Question

I have been struggling with a very weird issue that has suddenly popped up on the latest version of Eclipse Classic (4.2.2).

Everytime I try creating or refactoring a class or subclass in any of my projects (all Java) in my Eclipse workspace I get an error at the very top of my class that says

A class file was not written. The project may be inconsistent, if so try refreshing this project and building it

Again, this happens when I create new classes. And even when I rename current classes, then undo the renaming, its totally fine, but changing a single character in the name causes this error to happen for that specific class.

I have Auto Build on, and I tried multiple times to clean and refresh every project as well as restart Eclipse entirely.

I have literally no idea how to even start figuring out how to fix this. The solutions i've found through search didn't help, so i'm hoping I might find any clues here.

Prowel

Did you try what it suggests, which is to right-click on your project and select "refresh" ? – Schlosser

I did many times, and i'm pretty sure cleaning the project with auto build is the same thing as refreshing. – Prowel

Did you configure anything in the build path? Maybe excluded / included classes? I will also suggest that you start a new workspace and copy the source files into it. – Rhizopod

I tried both and there seems to be nothing different about the build path and importing to a new workplace doesnt fix the issue. – Prowel

One very curious thing that has hit me a couple of times with Eclipse is a bug(or feature?) in Windows, where full path of a file exceeds some number of characters (512?). In this case, Eclipse will silently fail to write the file, but don't realize until later. – Buhler

I know about the 512 character limit issue and I already checked to make sure none of my classes exceed that number of characters. – Prowel

I also experienced this issue. It turns out my disk drive was full. This is usually one of the first things to check when an app starts playing up. iTunes goes bonkers, as does Photoshop. Free up space and do a clean to fix up. – Bobbibobbie

Answer 1

I had the same problem and here's how I solved it in the end: It turned out that the disc space on the drive where workspace resides was full.

Silly mistake but worth checking.

Dibble

This does in fact answer the question. He was saying that the solution is to have some disk space on the drive where your workspace is, which is what solved my problem. – Cruciform

Eclipse should check for storage space, that is so simple to do, instead of creating that error. This solved for me too, neither cleaning/rebuilding worked (of course). Out of complete despair, he asked for a solution and this is the solution, so this answers the question. – Matchboard

I also just had the problem (Eclipse 4.7.3a), and in my case the cause was that a directory within the output directory (/target) lay on a faulty SSD "sector". So neither Eclipse nor Windows could write to that directory, nor delete it (e.g. with clean). After 1,5hrs of CHKDSK it worked again. – Generalissimo

Answer 2

In my case, this was caused by the fact that the build output directories were owned by a different user, and Eclipse could not write into them.

Sula

Answer 3

I had the same issues, the following worked for me:

1. Right click eclipse then running "as an Administrator"
2. Click Project > Clean.

Stabilize

Answer 4

Clean your workspace by starting eclipse from the command line with the -clean argument :

eclipse -clean

See also How to run eclipse in clean mode? and what happens if we do so?

Widen

This worked for me, I copy a lot of code over manually from my customers workstation (long story), and try to match the folder structures up but some of the security settings coming across are muddled. So using Project -> Clean... from the menu resolved this for me! – Verona

Once we clean the workspace with command prompt "eclipse.bat" -clean, as the workspace opens I gave project clean and the error is gone. After that we can start as usual through start menu without any specific arguments to it. – Leighannleighland

Answer 5

I solved this problem by running Eclipse as root.

Chiba

Answer 6

I had the same issue on Mac OS X. I had a maven project.

Try running the following command on Terminal. This looks like an access issue.

sudo mvn clean

Provide password for admin user.

Then open Eclipse and refresh your project.

Watchband

Answer 7

We are using Eclipse here too and have to handle a workspace with more than 200 plug-ins. Every now and then people have similar problems with their workspace and inconsistencies reported in a weird way by Eclipse. What people here usually do is (next step only in case previous step didn't help): - trying to ContextMenu->Team->Clean/Refresh the whole workspace - creating a new workspace and check out all necessary files from the repository - reinstalling Eclipse to a new directory

From my experience after using the Eclipse IDE on a daily basis for many years, it doesn't make very much sense to waste too much time with these issues, unless they aren't solved by one of the steps above. It takes too much time to struggle with these things, while starting from scratch is done in an hour or less (and usually fixes the issue). If your Eclipse still behaves strangely it might make sense to go through your installed plug-ins. Not all external plug-ins follow the Eclipse guidelines and can seriously harm the performance and operational consistency of your Eclipse installation (E.g. Sonar Plug-in, Toad Plug-in, ...)

Stevie

Answer 8

In my case this kind of error caused due to disk space got full and it got resolved by just freeing disk space where eclipse have been installed. That is c/d/e drivers.

Senn

Answer 9

I come up with the same error, and in my case, this is because the permission of the project/bin directory is not recursively 775

I fixed it by:

1. Remove the project/bin directory: sudo rm -rf project/bin
2. Switch to Eclipse, rebuild the project: Project->Clean...

Then no errors.

Masterful

Answer 10

Try to launch Eclipse as Administrator.

Threepiece

Answer 11

I fixed it by:

1.Remove (delete the target folder) from the project/target

2.Switch to Eclipse, force maven update the project

no errors.

Outoftheway

Answer 12

In my case such error was caused by a question mark in a quoted method name (I use geb+spock combination for automated testing).
So this method name will throw an error "Do you want something?"()
And this will not "Do you want something"()

Garfieldgarfinkel

Answer 13

It may not be the best response but to fix it, I've just delete the error marker.

Incriminate

Answer 14

Had the same issue. but cleaning the project and restart eclipse didn't help and disk space was not the issue. Solved the issue by copy the code to notepad(just to not lose it) and then delete the class, recreate it and paste the code back in again.

Somerset

Answer 15

I solved it changed the owner of the project files. I changed from root(old owner) to user my current(user that i use with eclipse).

Larose

Answer 16

Just changed and saved java file to recompile the class. Then error disappeared.

Bannerol

Answer 17

I was try run

Project->Clean...

And Rebuild. My problem was resolved

Elegance

Answer 18

For linux (Debia) and working on Spring boot project (maven):

$ sudo mvn clean

Then open Eclipse and File -> Refresh.

Gateshead

Answer 19

I had same issue, it is something similar but this post didn't help in my case. I have many inner classes which is causing the compiler to create class names with all inner class names together that is creating class name more than 255 character file limit on NTFS! read it in some other blog. I thought it will be helpful to post here.

Ex : classA$InnerClassB$......InncerClassZ.class in target folder it won't generate the class if it exceeds this limit. Try renaming your inner class name shortened. In my case i have to add InnerclassZ as its exceeding its not generating class and Eclipse complaining.

A class file was not written. The project may be inconsistent, if so try refreshing....

I shortened InnerClassZ to IClassZ fixed the issue.

Underling

Answer 20

I had the same issue and it got fixed by running eclipse in administrator mode Eclipse Shortcut-->Right click-->More-->Run as Administrator

Literate

Answer 21

I've been throught that error once when I used wsdl2java to extract java classes from a wsdl, it turns out that all classes were created in the same "class", causing end classes with long names (error - File name too long). When I organized and rename some classes the error disappeared.

Defazio

Answer 22

I had this issue. I did the following, it resolved.

Open Eclipse in Administrator mode; Right click on eclipse.exe "Run as administrator" Clean all projects.

Granville

Answer 23

@Denny's answer put me on the right track, though in my case it was the target directory. I deleted it for some reason and something automatically recreated with owner root. Changing the directory owner was not enough as it contained files that were also owned by root. So make sure to really remove the complete content of the directory and to change the owner.

Rumormonger

Answer 24

In my case current user didn't have access to this project dir

Sports

Answer 25

I had the same issue, and the root cause was that some directories were owned by another user. I would not suggest to run eclipse by root user as you might later ran into other issues, instead just make the current user own everything inside the folder (and the folder itself):

sudo chown $USER:USERGROUP -R ~/path

sudo chown alice:sudo -R JavaProjects/

Vodka

Answer 26

In my case it was Carbonite trying to backup the class files using a poor internet connection... eclispe couldn't delete one or more class files because Carbonite had locked them.

Graehme

Answer 27

When some directories can not be written by Eclipse, eg because they are owned by root instead of normal user, Eclipse starts throwing these "project may be inconsistent" errors instead of giving a proper error message.

I consider this an Eclipse bug. If target is not writable, report that, instead of "project may be inconsistent"

Problem was solved by fixing all offending target directories and reverting the project.

Probably can be done with "mvn clean" if your case revolves around maven and the problem is the target directories.

In my case I guess I accidentally built the project with "mvn package" while being root instead of normal user.

Paragon

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Answer 28

It happened to me when I ran eclipse with;

./eclipse

after running it like;

sudo ./eclipse

So, I tried with sudo again and it worked, probably running it with administrator mode will solve the issue.

Sarraute

Answer 29

Before giving a try to the above solutions. Just cleaned the project and it worked.

Shortage