I was looking at my code today and my project was giving me errors so I ended up deleting the thing (It had some code I was done with). Next I went to create a new project my the same name but when I did it gave me the same project with all the old .java files inside. So I went on to trying to make the name in lowercase and eclipse game me this "error" if you would even call it that???
Stack Overflow said I had to use a link to the image so please don't say "you broke the rules".
Normally whenever one deletes a project in Eclipse it will ask if you want to delete the entire project contents on the disk. Like so:
Deleting Eclipse project
If not, check your projects folder in Eclipse via Finder to make sure that entire folder is deleted.
You can change your workspace location in eclipse or move the old project to other location from your location. Hope this will fix your problem
I have a class BaseLoginDialog under a dependency which needs to be modified as it is not extendable out of the box. For this reason, I have created another file BaseLoginDialog under my project's module with the same package path as the original BaseLoginDialog. After adding some new methods in my own local BaseLoginDialog, I cannot use them anywhere in my project without IDEA complaining about the method not being declared. However, the project still compiles and the methods work fine on runtime. If I click the import to browse to the file, IntelliJ still links to the old file but it seems to correctly compile with the new one.
How can I go about fixing this issue? Always having error lines and red markers everywhere makes it confusing when coding.
Some background:
The project uses Gradle for the dependencies and compilation. Compiling and running works both with Gradle and with the IntelliJ run operation, it is only the errors being incorrectly displayed that is an issue.
The Grade file adds the required libraries as dependencies. Even though Gradle has both the source and class files, opening a file imported through Gradle still links to the class files. To get around this I also added the required files as sources under Libraries.
Any help would be appreciated, thanks!
EDIT:
Switched to use a Maven repo on the project, now I don't need to additionally add libraries anymore but this problem still persists.
If two classes of the same name and package exists in the classpath of an application, it's the one that is contained in the first dependency on the command line that gets used.
In IntelliJ, you can reorder dependencies, so you can put your local dependency before the other library. I'm not sure if that works with gradle projects, however.
But I don't think that's a good practice? Why can't you put the extra methods in a subclass, e.g. EnhancedLoginDialog, and use that one?
Or, if the original library is open source, fork it, make the changes and install it as a custom version, e.g. dialogs-1.0-CUSTOM-1.jar, and use this version in your project. And while you're at it, create a pull request for the library's maintainer to include your fixes in the next version :-)
I have resolved the issue.
The file I was copying into my local files was BaseLoginDialog. The file showing errors was my NewLoginDialog which extends LoginDialog which extends BaseLoginDialog. It seems that when IntelliJ goes to my NewLoginDialog, it sees that I have extended LoginDialog. Therefore it jumps into the library files and finds that LoginDialog extends BaseLoginDialog, now when it goes to find BaseLoginDialog, it uses the library files and ignores my local copy of BaseLoginDialog.
Essentially, once IntelliJ branches into a library, it does not move back out when looking for additional files if it can already find it inside the library.
To solve this issue, I simply also copied LoginDialog locally, even though it is identical (simply branched it and did not change anything). Now IntelliJ finds LoginDialog in my local files and as a result also finds BaseLoginDialog locally.
Hope this helps anyone having the same problem in the future.
I have no idea why, but from today Eclipse doesn't compile .java files into .class. I press the "Run" button and Eclipse only tries to run the program rather then compiles it first, so i get this error all the time:
Exception in thread "main" java.lang.NoClassDefFoundError
open problems view from window -> show view -> problems, if there's any error, fix it
eclipse will reject to compile if there is any problems in your project
Close Project -> Open Project -> Clean -> Refresh
Hope it helps for someone else
This problem happens when "for some reasons" your project is corrupted and has a red icon near the project's name in Eclipse. The solution is to save the project's folder, delete the project in Eclipse, than create the project again in Eclipse coping all the previous files saved.
I ran into this problem with Eclipse Luna, for some reason the Java builder was missing from the project. Verify that in your .project file you have something like
<buildSpec>
<buildCommand>
<name>org.eclipse.jdt.core.javabuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
You can also configure builders from Project Properties -> Builders
When I have had this exact same problem, its cause has always been the same and the solution has worked 100% of the time for me. It's caused by a missing jar file in the project's Java build path and it's indicated by a red exclamation point decoration on the project icon. To fix the problem, go to Project|Properties|Java Build Path, click on the Libraries tab and either remove or fix the path for all missing jar files. If your project is configured to rebuild automatically, it should start a build as soon as you apply your changes.
The eclipse needs to erase the output folder when building classes.
The folder is found on Project Properties -> Java Build Path -> Default Output Folder. It can differ from general output folder name found under Eclipse Preferences. If this output folder cannot be erased for some reason (for instance, on Windows, when a shell is opened on this location), the project is marked as corrupted (as Marco Micheli describes) and the classes then are not built.
You just need to make sure the output folder can be erased.
Yes I was facing this issue. Coz Eclipse cannot build the project for Build Path error. Check that your external jar files is not showing any error. Delete the Jar file which one is missing or which one is showing re color. delete that one. add a fresh one from the correct path or location. if all the error are gone. then in the project bin folder one class file will be created and then could not load main class error will be removed too.
there can be errors in your project, or other reasons like mentioned in above answers.
or you may be a fool like me
who moved the source code to other folder and not updated source path in project build properties. in this case it was not giving any error or class files too.
check that too.
goto
Project Properties -> Java Build Path -> Source
Add or Link new source folder location.
Do clean all projects ! This will erase all old class files, so eclipse is forced to generate them again.
Some times jars in the build path might be missing even though we are not using it. Since error is there, java files wont compile into classes.
Can check errors from problems view.
Either remove jars from build path or place the missing jars in the build path.
I had problem in eclipse for load module not found and no class file was getting created.
Solution: Go to Create New Project > Under JRE section Choose Use project Specific JRE.
Now Class files are created.
Please check if all the jars are there in your build path settings.
If any jar is missing this issue might come.
I had this problem, I tried the clean, the build manually, open, closing the project, deleting, and open, etc., nothing works, and after 4 hours I get a workaround what works for me.
Please, Make a RAR, ZIP, or copy from your entire project folder as a backup if it doesn't work and you mess around, OK, now:
Clean the Project. It cleaned all my class files from the output folder, but doesn't generate the class files after the clean with the building (but we already know that)
Delete the project (warning, make sure the Delete contents is not selected or your project will dissapear). For me it says something about that desynchronysation with code mix, and hibernate, blabla)
Close myEclipse
Restart your computer.
Open myEclipse
Import the project with the option "Projects from folder or Archive", not with the "existing projects into workspace" option.
Myeclipse start to build the class files, I don't know why, but works for me, I hope this helps somebody else.
Also ensure that there are no projects with fatal errors (projects with ! symbol over it) in the build path of the project which is not generating classes under the bin directory
Just restart your machine.
Its weird but it helps we had loads of problems this type in our company for unknown yet reason. Always restarting the machine helped.
It was normally encountered while trying to run Junit tests and it could not find a class even when the Run configuration was pointed to /bin.
I encountered a similar problem: previously compiled and running java files couldn't run anymore. Eclipse showed "couldn't find class xxxx". When I checked bin folder, the previous .class files were gone. That's why Eclipse couldn't run the files, NOT because of errors in files. I don't know why it can't just re-compile the file, and why the .class file gone missing in the first place.
But I found a solution:
Simply create a dummy java file in the same package (without doing anything just create), then run it. Then magically all previous .class files came back. And I can run those files as before.
Just Remove Your all Jars (Libraries) from the Build Path and refresh and add all jars and clean and build the project
This is probably a rare event but I declared a servlet with annotations and left off the "/" before the servlet mapping name. I spent over an hour chasing my tail, installing new servers, thinking I might even need to re-install my IDE and it was this simple error! Every time I tried to load any page from my Dynamic Web Project I got a 404 error. I could not even load a plain vanilla html page. There really needs to be better error logging with the IDE and Server interaction as there was zero indication of the error and my servlet was never called at the start of my web app. Hope this helps save someone else some frustration. Always name your servlet with a / slash like /myServlet never just myServlet.
I tried many different potential solutions: cleaning, rebuilding, removing, re importing, Update Maven Project and nothing. I still couldn't run my app from Eclipse. In my case the reason was that I was running Eclipse using openjdk-11 while my project was in Java 8. After I've reconfigured Eclipse to be ran from Java 8 everything started to work (in eclipse.ini).
-vm
/usr/lib/jvm/jdk1.8.0_202/bin
I'll explain my solution to this problem: "eclipse not compiling java files into class files". I'm using Eclipse version '2020-03 (4.15.0)'. I have a project that is dependent on a java project. For the dependent project, I was not able to export a jar file containing the compiles classes and resources. To be more precise, the exported jar file did not contain any class files. The output bin folder for the project is empty after doing a project build. In examining the console output when I tried to build all projects indicated that the build failed because the dependent project was missing. In looking at one of the log outputs, I saw something indicating that the build failed because some eclipse class was missing.
One of the things I tried was to do an eclipse update. Eclipse offered up the list of changes and I tried to apply them, but the update failed. I tried to update several times but they all failed. Looking more carefully at the offered up list of updates I noticed that one of the suggested update involved "deleting" Java Development Tools. That line had an warning indicating that the entire feature could not be deleted due to other dependencies and that only the non dependent features would be deleted. Doesn't that sound suspicious. Why was the update trying to delete Java Development Tools? My speculation is that something got deleted from the Java Development tool that was causing the build process to fail. The missing class I saw earlier also suspiciously sounds like it might be part of the Java Development Tools feature.
So what I did to solve the problem was to reinstall eclipse. I used the eclipse loader application to do the reinstall. (Note, I did not uninstall it first). After the reinstall, the dependent project was able to produce classes, and things once again worked as they should.
I certainly don't know how the eclipse release got into this compromised state, but in my situation the re-install of eclipse was the only way I could find to resolve the problem.
There would be the case : if you have opened project explorer in eclipse then it may not show you classes generated under /**/build/classes, in such case open Navigator view of that project and check build directory under the same project.
I'm trying to export a small program that I have made in Eclipse Indigo today to an executable, however, every time I do so one of two problems occur. The program uses one resource which I was hoping to put inside of the JAR but Eclipse will not put in the executable jar no matter which option I tick when I export or which folder the resource is in - the first problem!
The second problem is that whenever I tell eclipse to "Extract required libraries into generated JAR" I receive the following error when I double click on the executable Jar:
Could not find the main class: main.Launcher. Program will exit.
I don't suppose that the second problem is too much of an issue at the minute but the first one is extremely frustrating so I would appreciate any help or advice. Thanks in advance.
(Strangely, and even more frustrating, if I go through the same process with a project I made a while ago with a previous version of Eclipse it works perfectly.)
The folder structure of the project is as follows:
In the project folder there are the following directories .settings, bin, src as default. I have put the resource, which is a png in the bin folder but I have also tried it in the src folder.
Can you give some details?
What is the structure of your eclipse project?
Of what type is the resource?
More important where in the project structure resides the resource file?
Is the folder of that resource file included as a source folder ? (seems to be a prerequiste to get exported to the jar)
Is it copied over to the bin folder when the project is built?
Many Thanks
Michael
Update:
I have built a very simple java project 1 Java class with a main method and put a sample png file in the source folder. I refreshed the project to have the png visible in the project, then I cleaned the project to have it build again, then I ran the Main class inside eclipse. This will give you a run configuration when exporting throught the wizard. Thereafter I exported the complete project as "runnable jar", selected the run configuration and selected "Copy required libraries in a sub-folder next to the generated JAR". The png was included and the Main class was found. The executable JAR could be executed.
(Environment: Eclipse Indigo R1, Ubuntu, JDK 6)
You might want to play through the complete sequence of steps I went through. Maybe eclipse just did not pick up a file or other updates.
regards, Mike
First of all, I would like to thank Mike (marksml) for being so helpful and attempting to provide a solution for my problem. Unfortunately, his answer did not work for me!
I began to look at all of my previous projects and noticed that the one I was having trouble with was the odd one out (because it was the only one that didn't work) and the factor that made it the odd one out, I found to be the JRE system library version. The project was using the JavaSE-1.7 library but when I changed it to the JavaSE-1.6 like my other projects were using it miraculously worked and exported flawlessly! I'm still curious as to why this is the case, but at least I have it working now...
With thanks and kind regards, Andy
I've got a Vaadin project that uses JIRA's SOAP API. It runs fine in Eclipse, but attempting to make it work in IntelliJ and with Maven is slowly driving me mad, though I feel I'm close to completion.
Whenever I deploy my application to a local Tomcat server, all I get is a stack trace caused by this:
java.lang.NoClassDefFoundError
be.azvub.jira.service.JiraSoapServiceServiceLocator.getJirasoapserviceV2(JiraSoapServiceServiceLocator.java:53)
This class exists, because nothing has changed since I moved them from eclipse and because I can open the .java file and see that there are no errors in there. I can remove the luine of code that makes the call to this class and all is well, so it's a localised problem. The problem class is in a different package from my Application class (which still works), where the call to it is made.
What's causing this problem and how can I fix it?
I had the same problem and fixed it now after debugging ...
IntelliJ usually auto-creates a folder /lib under your /src folder inside your project, and then it would tell your project that all LIBs are in there, on that basis; we usually assume that it's the place to put all your LIBs in there as well.
Although with that setup your project would compile fine since IntelliJ can link up to your JARs However, with that sort of setup Tomcat will fail to execute, since Tomcat expects to find the classes under /WEB-INF/lib,...
Therefore, the solution is to:
1) Drag your LIB folder (sorry I mean "/lib") from /src/lib to be
under /web/WEB-INF directory
2) You would get a warning about moving classes / JARs, say YES.
(You need to tell your project to re-map your existing pre-defined
LIBs to the new folder):
3) From the main menu, select FILE -> Project Structure
4) Select
Libraries from the left menu
5) If you don't see any existing libs, then you're done, click OK
6) If you do see libs in there, then:
7) Click on each LIB from the
middle-list, and then remove the ones that can't be located,
8) Re-add them again from the new location
9) Repeat (7) to all other LIBs.
10) OK,
RE-compile, your project should deploy on Tomcat now and work fine.
Regards
Heider
I don't know how I did it, but by fixing an unrelated problem, this got fixed along with it.
I changed the Web Resource Directory under File | Project Structure | Facets (So the app could find Vaadin's theme folder under the WebContent directory instead of the default src/main/webapp it was set to) Neither of the folders actually contain the class that was giving me problems.
I also forced Maven to reimport everything, as I have done several times before, but now I used the option to do so under the project's context menu in the Project Explorer instead of the Maven Projects tab, so maybe that made a difference? Maven is still largely voodoo to me, but at least everything seems to be working normally now.
But thank you for your assistance anyway.
My guess would be the build path, check to see if the class you are calling is present in the build path of the project.