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I use eclipse with maven integration for my java web application project. When you right click the project you can "refresh" the project. You can also use "maven -> update project". What is the difference between refresh and update?
Sometimes I got a red-x sign in my pom file (I don't think there is any error). When I use the "refresh", the red-x sign disappears. Any idea?
Another question is that when I update the project, in the property -> deployment assembly, the maven dependencies was removed (I manually added them when I created the project). How can I fix this?
Thanks
A quick google search yielded this result: What does Maven Update Project do in Eclipse?
The correct answer states:
It syncs the Eclipse project settings with that of the pom. If you for example change important plugin settings, such as the output java version, you will find that Eclipse will ask you to update the project and afterwards the configured Java runtime in the project will have changed to reflect what your Maven pom indicates. That is an important thing to keep in mind: the Maven pom is the lead in this kind of project setup. If you want settings to change, try to do that through the pom and not through Eclipse project settings directly or doing a project update might revert what you have changed. There are usually some things I have to correct myself anyway though, such as build path exclusions that m2eclipse likes to put in and strange deployment assembly configurations.
So in short,
Updating your project through maven synchronizes the settings with that of pom and keeps all the settings synchronized between the pom and the project.
Refreshing your project through eclipse will reload the project - that is reload all the files and apply any external changes from the files to the project.
Note that a maven update will cause a refresh of the project in eclipse.
FYI, here's what the official documentation states:
Refresh command
The official Eclipse Oxygen documentation has two distinct (yet similar) definitions:
In Workbench User Guide > Reference > User interface information > Workbench menus > File menu it reads
Refresh (F5)
Refreshes the resource with the contents in the file system.
In Java development user guide > Reference > Menus and Actions > File actions it reads
Refresh
Refreshes the content of the selected element with the local file system. When launched from no specific selection, this command refreshes all projects.
F5
Update Project command
Unfortunately, the only documented occurrence I have found in m2e documentation (see m2e 1.5 release notes) is utterly insufficient and barely related:
The Update Maven Project dialog (launched via Right-click project menu:Maven[Update Project…] or via kbd:[Alt-F5]), now shows a dirty overlay on projects which need updating.
Additionally, an “Add out-of-date” button adds all out-of-date (OOD) projects to the current selection. If an OOD project has not been selected, a warning is shown underneath the selection table with a link equivalent to “Add out-of-date”. Warning text and “Add out-of-date” button tooltip show a count of unselected OOD projects.
Related questions on the 'Update Project' command (or the 'Update Maven Project' dialog):
(Which, alas, however insightful the best answers are, still provide no official statement from m2e developers.)
https://stackoverflow.com/a/20547404/4883320
https://stackoverflow.com/a/42562054/4883320
While debugging a java app in eclipse I receive a "Source not found" error in two cases:
Stepping in to a file in a different project which is already imported
Stepping in to a file in an installed maven repository
The files are there, but eclipse won't step into them, instead it shows a button to "attach source"
I tried attaching (which opened a dialog to define a variable?!) and eclipse did jump to the file, but the debugger could not inspect any variables there. Also manually attaching the source for each dependency isn't practical, as in my case there are thousands of dependency files.
Why is this happening, and how can it be resolved?
Just 3 steps to configuration Eclipse IDE:
Note: After updating the Source Lookup paths, you'll have to stop and restart your debug session. Otherwise, the file with the missing source will continue to show "missing source".
Edit Source Lookup
Select the Edit Source Lookup... command [ Edit Source Lookup ] to open the Source Path Dialog, which allows you to make changes to the source lookup path of the selected debug target.
IMPORTANT Restart Eclipse after this last step.
Eclipse debugging works with the class actually loaded by the program.
The symptoms you describe sounds like the class in question was not found in the project, but in a distribution jar without debug info found before the project you are working with.
This can happen for several reasons but have a look at the location where the classes showing this behaviour is found (look in the navigation pane to identify it). You will most likely need to change the build path of the project to avoid using this jar and have the JVM use the project instead.
EDIT: Note that as of 2018 it is common to use a build framework like Maven, where the build path is managed by the m2e plugin so this problem should be very less frequent than when the question was asked. If you use Maven and m2e, make sure to enable Preferences / Maven / "Download Artifact Sources" or right-click the project, Maven / "Download Sources".
The symptoms perfectly describes the case when the found class doesn't have associated (or assigned) source.
You can associate the sources for JDK classes in Preferences > Java > Installed JRE. If JRE (not JDK) is detected as default JRE to be used, then your JDK classes won't have attached sources. Note that, not all of the JDK classes have provided sources, some of them are distributed in binary form only.
Classes from project's build path, added manually requires that you manually attach the associated source. The source can reside in a zip or jar file, in the workspace or in the filesystem. Eclipse will scan the zip, so your sources doesn't have to be in the root of the archive file, for example.
Classes, from dependencies coming from another plugins (maven, PDE, etc.). In this case, it is up to the plugin how the source will be provided.
PDE will require that each plugin have corresponding XXX.source bundle, which contains the source of the plugin. More information can be found here and here.
m2eclipse can fetch sources and javadocs for Maven dependencies if they are available. This feature should be enabled m2eclipse preferences (the option was named something like "Download source and javadocs".
For other plugins, you'll need to consult their documentation
Classes, which are loaded from your project are automatically matched with the sources from the project.
But what if Eclipse still suggest that you attach source, even if I correctly set my classes and their sources:
This almost always means that Eclipse is finding the class from different place than you expect. Inspect your source lookup path to see where it might get the wrong class. Update the path accordingly to your findings.
Eclipse doesn't find anything at all, when breakpoint is hit:
This happens, when you are source lookup path doesn't contain the class, which is currently loaded in the runtime. Even if the class is in the workspace, it can be invisible to the launch configuration, because Eclipse follows the source lookup path strictly and attaches only the dependencies of the project, which is currently debugged.
An exception is the debugging bundles in PDE. In this case, because the runtime is composed from multiple projects, which doesn't have to declare dependencies on one another, Eclipse will automatically find the class in the workspace, even if it is not available in the source lookup path.
I cannot see the variables when I hit a breakpoint or it just opens the source, but doesn't select the breakpoint line:
This means that in the runtime, either the JVM or the classes themselves doesn't have the necessary debug information. Each time classes are compiled, debug information can be attached. To reduce the storage space of the classes, sometimes this information is omitted, which makes debugging such code a pain. Your only chance is to try and recompile with debug enabled.
Eclipse source viewer shows different lines than those that are actually executed:
It sometimes can show that empty space is executed as well. This means that your sources doesn't match your runtime version of the classes. Even if you think that this is not possible, it is, so make sure you setup the correct sources. Or your runtime match your latest changes, depending on what are you trying to do.
From http://www.coderanch.com/t/587493/vc/Debugging-Eclipse-Source
"When running in debug mode, right click on the running thread (in threads tab) and select Edit Source Lookup. At this point, you should be able to add the necessary project/jar which contains your source code."
I added my current project in this way, and it solved my problem
I had similar problem with my eclipse maven project. I fought with this issue quite a long time then I tried to rebuild project with
mvn clean eclipse:eclipse
and it helped.
Note: Using this approach will confuse the m2e plugin since the two approaches are very different. m2e adds a virtual node to your project called "Maven Dependencies" and asks Maven to add all dependencies there.
mvn eclipse:eclipse, on the other hand, will create a lot of individual entries in the file .classpath. Eclipse will handle them as if you manually added JARs to your project.
Unless you know how the classpath in Eclipse works, this approach is not recommended.
I was facing the same issue,I followed the bellow steps.
Window => Preferences => Java => Installed JREs,
You see in the above screen Jre1.8.0_12 is selected.
select the JRE you are using and click Edit. Now You should see the bellow screen.
Click on the directory, browse for Jdk, It should look like bellow screen.
click ok, and its done
I had the problem that my Eclipse was not debugging the source code of my project. I was getting a blank page with "Source code node found".
Please click the Attach source code button. Then delete the "default" folder then click add and go to your project location and attach. This worked for me
Remove the existing Debug Configuration and create a new one. That should resolve the problem.
None of the mentioned answer worked for me.
To resolve this issue i have to follow bellow steps:
Right click on Java HotSpot(TM) 64 Bit server.
Select "Edit Source Lookup".
Click on "Add".
Select "File System Directory" instead of Java project.
Select Root directory of your project.
Check "Search Subfolders".
Click Ok ok ok.
Thanks.
Click -> Edit Source Lookup Path
after then
Click -> Add finally select Java project and select project path.
Source: https://www.youtube.com/watch?v=IGIKPY6q1Qw
In my case, even after Editing source lookup and Adding project, it didn't worked. I configured the Build path of the project.
After that, I selected JRE System Library and it worked.
Evidently, Eclipse does not automatically know where the source code for the dependent jars are. It is not clear why debugger could not inspect variables once the source was attached. One possibility is incorrect/incompatible source.
Assuming you have a maven project and the sources of the dependencies are downloaded and available in the local repository, you may want to install m2eclipse, the maven eclipse plugin and see if that helps in addressing your issue.
You might have source code of a dependency accessible to Eclipse. But Eclipse does not know for source code for code that is dynamically loaded. E.g. through Maven.
In case of Maven, I recommend that you use run-jetty-run plugin:
http://code.google.com/p/run-jetty-run/
As a workaround you can also connect to a running JVM with the debugger and you will see the code.
Alternatively you can use Dynamic Source Lookup plugin for Eclipse from here:
https://github.com/ifedorenko/com.ifedorenko.m2e.sourcelookup
Unfortunately it didn't helped me as it has issues with Windows paths with spaces.
I have filled an enhancement request on Eclipse Bugzilla and if you agree this issue "Source not found" should vanish forever, please vote for it here:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=384065
Thanks!
Sasa
In my case in "Attach Source", I added the other maven project directory in the "Source Attachment Configuration" panel. Adding the latest version jar from the m2 repository din't work. All the classes from the other maven project failed to open.
Here test was my other maven project containing all the java sources.
I had the very same problem. In my case, I've disabled Window-Preferences-Java-Debug [Suspend execution on uncaught exceptions]. Then, the console showed me the correct error: my MySql user hadn't privileges to access the database. According to this topic.
Info: This is a possible solution, when you use maven (pom.xml) with couple of projects.
If you are working with maven, make sure what version you are taking inside the according pom.xml (e. g. 1.0.1-SNAPSHOT ).
It might be possible that your code is up-to-date, but your pom.xml dependencies are still taking the old JAR's/Snapshots (with the old code).
Finding the problem:
Try to debug the according file.
Therefore, set a breakpoint in the relevant code area.
When "source not found" appears, make sure to bind in the right project (where the .java file can be found).
The compile .class file opens up in the IDE editor.
Click "Link with Editor" to find the according JAR/Snapshot.
Now make sure that this JAR is the most recent one. Possibly there is a newer one. In that case, write the most recent version number in the pom.xml.
Then do a maven update and build (e. g. "mvn clean install -U") in the right project directory.
If you are on eclipse or STS please install and Use GC(GrepCode Plugin) ,some time you don't need to attach the source .zip file into your project path so GrepCode works fine for you.
I've had a related issue in connection with Glassfish server debugging in Eclipse.
This was brought about by loading the source code from a different repository (changing from SVN to GitHub). In the process, the wrong compiled classes were used by the Glassfish server and hence, the source and run time would be out of sync with break points appearing on empty lines.
To solve this, rename or delete the top folder of the classes directory and Glassfish will recreate the whole class directory tree including updating the class files with the correctly compiled version.
The classes directory is located in: /workspace/glassfish3122eclipsedefaultdomain/eclipseApps/< your Web Application>/WEB-INF/classes
In my case with tomcat projects I have checked project here:
Window - Preferences - Tomcat - Source Path - Add java projects to source path
In my case the Maven version of the other referenced project didn't match the version of the test project. Once they were the same, the problem disappeared.
When running in debug mode, click Edit Source Lookup after suspended from thread. At this point, we should be able to add the necessary project/jar which contains your source code.
After I added my current project in this way, and it solved my problem. Thanks
If you want to attach source code to any JAR by auto-downloading, try using this Eclipse plugin Java Source Attacher
I had this problem while working on java code to do process on a excel file containing a data set, then convert it to .csv file, i tried answers to this post, but they did not work.
the problem was the jar files themselves. after downloading needed jar files one by one(older releases) and add them to my project, "source not found" error vanished.
maybe you can check your jar files.
hope this would help.
this worked for me
right click on project -> Properties -> Deployment Assembly -> add your jar
Go to Debug configuration in eclipse and use below goal to run your application.
-Dmaven.surefire.debug
e.g
-Dmaven.surefire.debug exec:java
Well, here's what worked for me. I tried every possible solution on StackOverflow that there was. I tried changing my source location in the debug menu, I installed the m2e Eclipse plugin, I changed from embedded Maven, and I installed the run-jetty-run and nothing worked. Now, I will caveat that I was not trying to view an external person's source code, I just wanted to see my OWN code, but every time I "stepped in" to my methods that I wrote that were in MY project, I got the "Source now found" error.
After finally asking an expert, my issue was that the first thing Eclipse was doing was calling a ClassLoader, which you can see from the debug stack. All I had to do was F6 (step over) and then it took me back to my original call and then F5 (step in). And there was my code. Sigh...such a simple fix but an hour wasted.
For beginners,
There is a possibility that the jar file is a part of the project which you have not yet included in the Eclipse workspace.
For that, you need to know the project name of the jar file.
Say for example, its abc-18.0.0-SNAPSHOT.jar, it means that the project you are supposed to include in your workspace is abc.
I had the same issue with eclipse 2019-03 (4.11.0) and I was only able to solve this by doing the debugging via remote debugging instead of directly launching it in debug mode.
Attach source -> Add -> External Archive -> select the jar -> open -> done
the catch is look for the sources jar and attach this jar.
for example the jar ends with "-sources" Stax2-api-3.4.1-sources
sometimes these thing happens because of the version also like if you are using latest
version in that case it may arise try to use older version it will work.
I have create multi-module maven project in Eclipse IDE (already installed M2Eclipse plugin). There I can build my project successfully. But after build also it shows errors icon in my every module project. What kind of issue it can be?
Thank You.
Without knowing what errors you are seeing I am going to assume that your issue is with eclipse project properties (build path, src directory specification, output classes directory, etc).
You tagged m2eclipse plugin, so you should be able to right click on your project in eclipse select maven->update project configuration. If you do not see that option under maven then you should first see an option called maven->enable dependency management. Click that first and then you should be able to see update project configuration option.
If this does not fix it, then open your project directory containing the pom.xml file in command prompt and run mvn eclipse:eclipse.
One of the above should resolve those pesky error messages provided that your maven build itself is successful.
In eclipse open the Markers Tab (You can open it from Window -> Show View -> searching Markers)
It will show all the related errors with your project. You can identify your problems related to your problem, and solve accordingly. Sometimes it shows Quick Fix option, which is helpful.
For me, the above solution listed out by #CoolBeans was not working out, so i searched further and found out the following:
Go to Problems windows(present besides of Console window). If it is not there then click on Window-> Show View -> Problems
Inside Problems you will be able to see the Errors Description related to your project. In my case it was "java compiler level does not match the version of the installed java project facet". If that is the case for you as well, just follow below steps:
Right Click Project -> Properties
Click Project Facets(present in the left hand side list)
Choose the correct java version in Java Project Facet
Click Apply
That's it!
I am trying to run my project, but Eclipse is saying I have errors. But there are no errors, just a red cross where the project name is. I have tried deleting the R.java and generating a new one, but that didn't work.
Take a look at
Window → Show View → Problems
or
Window → Show View → Error Log
Based on the error you showed ('footballforum' is missing required Java project: 'ApiDemos'), I would check your build path. Right-click the footballforum project and choose Build Path > Configure Build Path. Make sure ApiDemos is on the projects tab of the build path options.
This happens from time to time in Eclipse. In the "Project" menu there's a "Clean" option, that usually takes care of the problem.
Go to project>clean and select the project which display error from check box and click ok , it will clear the error for you.
Click the tab which display build automatically in the project menu
And if this also does not work than restart the eclipse and try again it will work.
For me, this happens with Maven and Eclipse/STS whenever I update my IDE or import an existing Maven project. Go to the "Problems tab" (Window -> Show View -> Problems) and see what it says. Recently, the problems tab showed Project configuration is not up-to-date ... and suggested that I use Maven to update my project configuration, and this solved the "red X" problem. To do this, in the "Project Explorer" view, trigger the context menu and select Maven -> Update Project, as seen in this screenshot:
If you see the error in problem panel it will say : Description Resource Path Location Type
Project configuration is not up-to-date with pom.xml. Select: Maven->Update Project... from the project context menu or use Quick Fix.
Solution : Right click on project > select : Maven->Update Project
Error gone.
Right Click on Project -> Build Path -> Configure Build Path. Check if Maven Dependencies is there in list, if not then update maven project by
Right Click on Project -> Maven -> Update Project
I had a red X on a folder, but not on any of the files inside it. The only thing that fixed it was clicking and dragging some of the files from the problem folder into another folder, and then performing Maven -> Update Project. I could then drag the files back without the red X returning.
Ensure you have Project | Build Automatically flagged. I ran into this issue too and turning that on fixed the problem.
I just removed all the private libraries in JavaBuildPath and added the jars again.. It worked
I came across the same issue while working on a selenium project(maven). The Project folder and pom.xml were showing red cross symbol. This was coming as i had the test datasheet open. I could remove the error by just closing the datasheet and the never faced the issue again
In my Spring Boot application, I right-clicked on my Application class -> run as -> Java Application -> Proceed(All errors will be cleared)
For some reason Eclipse is no longer showing me Java compilation Errors in the Problems View.
It is still showing Warnings.
This has suddenly happened and I cannot think of anything that I have changed which would affect this.
I am using the "Maven Integration for Eclipse" plugin but I have been for some time - not sure if this could have affected it or not.
Any ideas?
I had same problem and randomly did such things as (several times):
1) Project->Clean...,
2) close and open Eclipse again,
3) Run As...
And it started to work again, without changing configuration.
Right-click your project and go to Properties > Java Build Path > Source.
Make sure your source directory (for example MyProject/src) is listed as a Source folder. Otherwise you won't get any red markers.
I want to post my story here if Google brings you to this question.
Somehow, "Project->Build Automatically" got turned off.
Turning it back on produces correct errors list.
In my case it has nothing to do with m2e 1.0. This is default behavior for any Java project and goes back as far as Ganymede ( at the point of writing this post I am running Indigo )
This is not totally an answer to your question, but is related. I thought eclipse stopped showing red/yellow flags next to files in my project. The solution was very simple - I was looking at the Navigator tab (which doesn't show error/warning flags) instead of the Package Explorer tab.
I installed and deinstalled ajdt-plugin and got the same problem.
Check <Project><Properties><Builders>.
It should have a 'Java Builder'.
This code should be in the .project file (file is in the root of your project):
<buildSpec>
<buildCommand>
<name>org.eclipse.jdt.core.javabuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
<natures>
<nature>org.eclipse.jdt.core.javanature</nature>
</natures>
Check your source directory is listed in source folder of project
Right-click your project > Build Path > Configure Build Path > Source.
If you are using multiple projects (as dependencies)
Project->Clean...,
Check "Build Automatically" is enabled or not.
project > Build Automatically
What worked for me is creating a New Problems View (this option is accessible from the three-dots View options):
The new View does show all the warnings and errors that were detected:
I was experiencing this problem as well today. The other solutions presented here (such as cleaning the project and restarting Eclipse) did not work or were not applicable to my setup. What did work for me was right-clicking on the project in the Package Explorer and selecting Maven->Update Project Configuration. Evidently some source folder restructuring I had done the previous day had caused Maven to lose track of things, and issuing this command fixed everything.
At the top right corner of the problems window (next to minimize) there is a small arrow-icon. Click it and select "Configure filters". There is a severity filter that might have been activated.
I have the same problem in slight different situation. I have a parent POM and multiple modules under it. Project was existing and I imported it into eclipse. I can change the "Dependency management" only to parent project but not projects under it. They are not showing any compilation warnings.
Next I'm going to try to change them all into individual projects... that's not what I wanted, but I haven't been able to solve this otherwise...
I have also faced the same problem.
After installing m2eclipse plugin, i was not getting any Java compilation errors.
My solution was to enable dependency management by Select Project -> Right Click (to get context menu) -> m2 Maven -> Enable dependency management.
Now i am able to view Java Compilation Errors.
This is normal problem. In wich order and export function sometimes get turned off.
right click on project<properties< there u hav option
build path < and there ORDER AND EXPORT< click right all the options....all the things are right back.
On Ganymede, check the configuration of the Problem view:
('Configure content') It can be set on 'any element in the same project' and you might currently select an element from the project.
Or it might be set on a working set, and this working set has been modified
Make sure that 'Match any configuration' is selected.
In my case Eclipse wasn't properly picking up a Java project that a current project was dependent on.
You can go to Project > BuildPath > Configure BuildPath and then delete and re-add the project.
There are obviously several reasons why this might occur, and I thought I'd add the solution to my issue. (I have a java project into which I have imported files with virtual links)
If you have a situation like mine, you will have another folder on the same level as your 'src' folder. If you do, right-click on that other folder, then select 'Build Path' > 'Add to Build Path' (if you see 'Build Path' > 'Remove from Build Path', then it had already been added.)
To further configure the Build Path, right click on your top level project dir, and select 'Build Path' > 'Configure Build Path'. Your folders should show up in the 'Source' tab.
To configure what errors you see, Click on Java Compiler > Errors/Warnings and then click 'Configure Workspace Settings'. That is the same as going to Window > Preferences > Java > Compiler > Errors/Warnings. If you don't want Eclipse to ignore something, then just change it to Warning.
Try following:
Open Problems window (Windows -> Show View -> Problems)
Right click on the error and then Quick Fix
This procedure helped me solve the same problem.
If you have reached here that means all the other solutions did not work for you.
One reason could be your source folder is not a java project.
Solution would be to run below command on the source folder
mvn eclipse:eclipse
This worked for me.
If this also doesn't work then try removing .classpath and .project file and run the above command again
I could reproduce this issue by creating an enumeration with a non-static member class and a static block enumerating its values:
public enum Foo {
Dummy(new Bar [] {new Bar()});
static {
for (Foo foo: Foo.values());
}
private Foo(Bar [] params) {}
public class Bar {}
}
This class breaks the Ganymede compiler. If you delete the line in the static initializer block, the code compiles correctly again, and you get the error that there is no enclosing instance for the new Bar() call, as expected.
-- correction: The above holds only if the project has gaeNature from Google Appengine. However, if you get an error similar as mentioned in the original question, you might be encountering another java compiler bug ...
I have the same issue with Eclipse Helios and the m2eclipse plugin. They just can't seem to get this thing to work with WTP or WPT or whatever the blasted acronym is.
If I do a clean on the project and watch the Maven console then I can see the compilation issues in the console but eclipse won't touch it. It seems eclipse or WTP/WPT and m2eclipse are busy playing slap hands.
I experienced that problem with a MapReduce project. I closed the error window and never came back after doing what the other answers suggested.
Click on the bottom left -> Other -> Problems
Kepler SP2, Java Project (Web Driver), and we use Gradle instead of Maven
None of the above helped, what did fix the problem for me was to select my projects (r-Click) > Gradle > Refresh All
Pointing the source(src) folder to the build path will solve this easily
to do so
right click on the project > build path > configure build path > java build path > source > add folder and click Apply
My mistake was that I was creating classes in resource package...
Creating classes in src/main/java solved the issue.
Check your filters, sometimes problem view could be scoped to a working set that you are not currently working in. Also, you can check other configurations for the problem view.
Problem in .classpath
I did "Replace with HEAD revision" to get back the version that I had in the repository Git and the errors appear again.
Duplicates in build path
In my case, errors were not showing up in the Problems View or Package Explorer views because my build path had duplicate entries for src and test directories:
Removing these from Project -> Properties -> Build Path (and just leaving one each) did the trick.
In my case I setted a old workspace and it was the problem.
Try to set a new folder for workspace
If "Debug" has been recently activated then check the top right of the program (under the Minimise button) and click back onto Java.