Problem with Java Buildpath in Eclipse - java

In eclipse I have an error related to my build path.
The error:
Project 'XX' is missing required library: 'middlegen-2.1.jar'
But the library is deleted before the build path configuration.
Is there perhaps a problem with cache or so?
Has anyone an idea why eclipse say that the library is required even though the library was deleted before the build path configuration.
With Best

I guess you've deleted the library from a directory, but you've not updated the project Build Path. Right click on the project name, select "Properties", go to "Java Build Path", choose the "Libraries" tab, and see that your library is not in the list. If it's still in that list, remove it with the "Remove" button.

This error is due to probably either missing required library or due to caching of eclipse
Solution 1
Open project explorer window.
Right click on the project and goto Buildpath -> ConfigureBuildPath
Under the libraries tab check whether all the used jar files are physically located in the directory/web application library.If something is showing "RED X" mark then fix them by either putting the jar in the place or remove it or add it newly using add JARs
Solution 2
1.Try cleaning the project's using Menu->Project->clean (select the projects and clean it)
Solution 3
If your build path is very clear i.e no Red "x" marks then the error could be of eclipse caching.Then do below step
1.Right click on the project choose "close project".
2.Once the project is closed again right click on the project select open project
This solution will clear the eclipse cache.
Hope any of the solution should resolve your problem.

I had this same problem, but the steps above didn't help. I did a search through files in the Eclipse workspace and found files named .markers and .markers.snap that contained the bad path names under the folders in .projects that were named for the projects that weren't building. I exited Eclipse, backed up those files, removed them from the Eclipse workspace, and restarted Eclipse. The problem went away.

Your project configuration includes a reference to middlegen-2.1.jar on the build path. That file is missing. You can either a) put the file there, b) change the configuration to point to the file in another location, or c) remove the reference, cross your fingers, and hope the project compiles and runs without the jar.
I don't know what "the library was deleted soon" means, so if that is important to your question, you might want to rephrase.

Related

Zip Referenced Libraries into Eclipse project

I have no experience with package structure. I added two external libraries (from Joda) to my eclipse project. The code makes use of the libraries with no problems. However, when I export the Archived File and open it on another computer, the libraries are no where to be found. Much sadness.The error looks like a little red exclamation point next to my project in the package explorer. Checkboxes next to the libraries have been checked/applied.
Right click on your project
Navigate to build paths -> configure build path
In order and export tab check whether the library is in the list or not
If it is not selected, tick the Checkbox and click apply
Someone told me that I need to export it as a executable jar.

I have enabled the "Build Automatically" option in eclipse, still it is not generating the class files

I have tried refresh, clean and also "build project" . Still class files are not being generated.
The exact error is " A cycle was detected in the build path of project_1 The cycle consists of Proj_2,Proj_3 etc"
Any help is appreciated.
Thanks
A build cycle is when you have cyclic dependencies, e.g. proj_1 needs proj_2, proj_2 needs proj_3 and proj_3 needs proj_1 again. When building, eclipse uses the dependency information to determine which projects to build first, but when there are cyclic dependencies, it cannot decide.
See if you can break the cycle, e.g. in this case by removing proj_1 from the build path of proj_3. Maybe you need to move some classes to a different project so you don't need the dependency.
try this, Open up Project->Properties and select Java Build Path from the list. In the Libraries tab you'll see a button labeled "Add Class Folder..." Point that to the location of your .class file. check each tab to see if there are any build path problems.. then refresh or restart the eclipse..
right click on project (for maven project) > java build path > check source folder, there you will see source folder and corresponding output folder where your classes will reside, if this is not there then your build will not create classes.. or java project check in bin folder as said by vijay
i found this stack link for you, check this
A cycle was detected in the build path of project xxx - Build Path Problem
or you can change cyclic dependency severity level to warning, check below
http://www.eclipsezone.com/eclipse/forums/t71727.html
go to project menu ..select the build automatically option.
go to project source folder, then look for bin folder you might hava .class files there.

eclipse doesn't compile the project

I had running project opened in eclipse. After an accidental restart of windows, now when I open the eclipse I see my project is marked with a little red cross. Now when I run the main method I get a java.lang.NoClassDefFoundError.
I have tried restarting eclipse, Project -> Clean but it doesn't solve the problem.
When I checked the project directory, inside 'target' folder there are no compiled .class files. I tried building the project but I can't get the compiled class files, which is the reason for the error.
How do I solve this?
I tried all the solutions here, but here's what worked for me.
First, remove the project from eclipse.
Then, in your project folder, delete the 2 files that eclipse creates. They're hidden, but they're called .project and .classpath.
Finally, add the project back into eclipse and eclipse will recreate those 2 files and a new configuration for your project.
My specific issue was that it a project that was missing a Java Builder because it thought it was a scala project. The only way for me to reset this was by removing the project, deleting the 2 files, and adding it back in.
Maybe Eclipse's workspace files have become corrupted. Restart Eclipse and choose a new workspace folder (or choose Switch workspace from the menu). Then import the project files into a new project.
Try deleting the run configuration and remaking.
If that doesn't work, open the class, ctrl+f11 to run. That will force Eclipse to update its classpaths & rebuild its main indexes.
To delete the configuration:
- Menu -> Run -> Run Configurations.
- Select your configuration
- Press delete or use the delete icon
If you are using maven, this will likely fix it: Right click your project -> Maven -> Update project.. (or alt + F5), select your project, make sure "Refresh workspace resources from local filesystem" is checked and click ok.
My eclipse project has similar issue though the error appeared slightly different. I imported a third party java project into Eclipse, with Project > Build Automatically checked, do a Project > Clean..., no classes were generated in the output bin folder. Tried different options, no luck.
I noticed a red exclamation mark at the top left corner of the project name.
Right click on project name, Properties > Java Build path, I saw "Build path entry is missing: cci/src". Manually created src folder, the red exclamation mark gone. Do a Project > clean..., project compilation successful
P.S. The eclipse project is not properly organized, there are no code under src folder. I suspected src folder went missing while checked in by original author since there are no code there.
Was having the same problem and finally found the glorious hint here.
In my project there is one *.scala File and Eclipse Neon is incompatible with the Scala IDE, thus there is no builder for scala and the whole project is not built.
After removing the Scala file and the Scala Package from the linked Libraries )Project Properties --> Build Path --> Libraries) and afterward re-adding the Java Builder (no idea why this one went missing, but here's a useful help on how to add the Java builder when missing), the project could be built and run again.
Try refreshing and then cleaning the project.
For me the problem is in missing jars,the jars were added first and the location of those jars where changed after.
So When I correctly added all the required jars again to the build path, it starts to build project correctly.

Java Eclipse - How do I change the classpath?

I copied an Eclipse project from my PC (eclipse is on drive D) to the laptop (eclipse is on drive c) but when I try to deploy the agents I have in my project I keep getting the following error:
The archive **D**:/eclipse/plugins/it.fbk.sra.ejade_0.9.0/lib/libjade4/commons-codec-1.3.jar which is referenced by the classpath does not exist.
I changed all the libraries' addresses to the correct ones (C:/eclipse/plugins/it.fbk.sra.ejade_0.9.0/lib/libjade4/__etc__) for all of them by right clicking the project > build path > configure build path... but that doesn't work. I also tried to refresh the project, restart eclipse but still nothing..
Any suggestions?
Thanks a lot!
First make sure that the .jar file is exist in the given path,if so then you can easily try making a new project and copy your material to it, and configure it to the .jar path.
If this doesn't work you may need to remove the temporary files from your project and eclipse on your laptop.
Also, please give more description about what happens on right clicking the project > build path > configure build path ?
Hope everything works well.
I had the same problem and just discovered the solution to this.
Go to project>properties>Java Build Path>Libraries>Add External JARS.
After specifying JAR file at a certain location, you will see it in previous window "JARs and class folders on the build path:" with "JAR_fileName - C:\YOURPATH".
Don't stop here instead click on the "+" button to the left to expand it, and IF it says "Source attachment: (NONE)", you double click it and add the path to the JAR file by selecting Workspace location.
This solved the problem for me.
Had the same problem and non of the above solutions worked.
This is how I fixed it.
go to your project folder
open .classpath file (enable view hidden files if its not showing)
edit the path
delete the project from workspace. Imp: Don't select (Delete project
content) checkbox when prompted. !!!
re-import the same project
I had the same issue...
I was refering jars from a mapped drive, when I moved them to my local drives, it started working fine. Also try giving a shorte path for the jars.

After checking out Subversion code into Eclipse, how do I get it to build?

This problem has been frustrating me for some time...
A lot of sites like Sourceforge use SVN or Subversion to manage their code. I have little problem compiling SVN code in C++, but when it comes to Java, my IDE gives me a headache.
I've installed Subclipse for SVN support for Eclipse, and it works. I can check out any code into my Workspace. Now Subclipse will put the whole thing into a special project of some sort that can't be compiled. So I search Google for something and I come up with modifying the eclipse XML file to specify the 'nature' to be a Java project.
Okay, now it's a Java project. Say I have a folder structure like:
\src
\data
\graphics
I get 800 compiler errors complaining the package name is org.company.SomePackage instead of src.org.company.SomePackage.
Then what I do is create packages called src, data, graphics, etc, instead of just folders. I cut and paste everything in the folders into the packages and finally I can compile it.
What is a better way to do this?
EDIT: I can only check out anything SVN as a SVN project, and there's no way within Eclipse to change that to a Java project. How can I check out the SVN as a java project in the first place?
I get 800 compiler errors complaining
the package name is
org.company.SomePackage instead of
src.org.company.SomePackage.
Right click on Project -> Properties -> Java Build Path -> Source Tab -> Add "src" as a source folder and remove any others.
it thinks your source is stored in root folder. you need to specify to the project that /src is the source folder.
In general when we have an Eclipse project, which contains Java code – but we didn’t set it up as a Java project when we created or checked out this project, we are struck. And Eclipse doesn’t allow to change the project type inside the Gui. So we need to add the java nature as below.
1. Close your project.
2. Open your project file (which is located in your root directory of the appropriate project) called .project with your default editor. Search for
< natures>
< /natures>
and change it to as below
< natures>
<nature>org.eclipse.jdt.core.javanature</nature>
< /natures>
Save the changed file.
3. Open the project again – now it should become a java project.
Then do the following as explained by Kevin
On the Project Explorer Window ->Right click on the specific Project -> Properties -> Java Build Path -> Source Tab -> Add "src" as a source folder and remove any others.
For me when I went into “Source Tab” – the “src” folder was already added, but it was not giving me the desired result (ie I was still not seeing the .java files in the project explorer window). So I removed the “src” filed that was already added in the Source Tab and then added them again. And then all worked fine.
You have to configure proper source paths. Some open source projects make this automatic by checking their .project and .classpath files in with the rest of their files. For others, you'll have exactly the problem you are having. You need to set the classpath so the Java compiler knows where to find the source. You right click on the project and select properties and configure an arbitrary classpath, but the answer given by Kevin is easier for a beginner.

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