How to run a modified java program in eclipse? - java

I have a project in Java which get a file using smb client. When I edit this code and run it again in Eclipse, it is not running my modified code but running the same old one.
Checklist:
I saved the file and made sure there are no write errors.
Build Automatically is enabled.
Run configuration is configured properly.
There are no unresolved errors.
what am i doing wrong?

To find out whether Eclipse has really compiled your code, have a look into the bin/ folder of the project and check the date of the .class files in there. You will have to do this outside of Eclipse since it hides the content of this folder by default.
Use "Clean Project" to force a rebuild.
If that looks correct, the next step is to go to the Debug Perspective. Open the Properties Dialog for the process. Eclipse will then show you the classpath that it used to start the process. Make sure the paths are correct.

Delete bin folder data and clean project. To clean project:
Go on Project-->Clean-->select your project-->clean-->build project
This will solve your problem, if this does not work, please write a Hello world program and check this works or not. If this is also not working, check your Eclipse

Related

IntelliJ only compiles files once

IntelliJ (Ultimate 2018.1) is not building my project properly. The project is using Maven which doesn't seem to have any problems (all libs are there). The problem is as follows:
Everytime I start up IntelliJ, I am able to build all changes exactly one time. I can change contents of my files and those changes will be contained in the build. But every change I do after that first build is ignored by the build tool. So, every time I build the project (ctrl+f9) after that, I get "All files are up-to-date" and nothing is compiled. (If I am running the app on the application server and try a hot swap, the build says "loaded classes are up to date ...")
Only a restart of the IDE lets me rebuild the project.
Edit: As I just found out, a restart of the IDE is not the only possibility to make a build possible again. In the state of not being able to compile, I changed a setting in the compiler settings. After that, I was able to build again. But only once. I then changed the setting back and well, I could build again. Looks like something odd in the IDE. /Edit
Edit2: Oddly enough, the explicit compiling of the class (ctrl+shift+f9) is working. So the problem circles around the compiling of the whole project. While this is making IntelliJ usable again, it's error prone regarding multiple changed files... /Edit2
A few notes and configurations of the project:
The build produces a .war
It is deployed on a wildfly (which is not started once in this cycle, so this shouldn't be the root of the problem)
The exact same project was formerly developed in Eclipse where building and Hot-Swap worked flawlessly (and still do when I try Eclipse again)
Maven Config:
Compiler config:
Check with Intellij version. As I am using 1.4 community edition and for me its running proper.
Even I have updated few dependencies after building First Time and it get's rebuild automatically.
So for my understanding what you can do it just check with the Intellij update or change the default directory and rebuild it.
The problem with the "Build Project" command is the source discovery of IntelliJ. A long time ago, we made the choice to place our sources inside a folder named ".git" (not the folder in the repository), so IntelliJ had problems to discover the code inside that directory. The reason for that was an old approach of Eclipse to clone repositories into a .git folder. The directory looked like this:
C:\dev\.git\workspace and inside that folder was another .git folder (from the repository).
So, the answer is:
Don't put your git repository in a folder named ".git" or IntelliJ will not compile it (unless you only compile class wise).

IntelliJ Not Saving Changes

I've been encountering an issue with IntelliJ. Every time I save a change to some FXML I'm editing, the changes are removed upon executing the program.
For instance, I will change the 50.0 above into 160.0, and once I run the program the code changes back to 50.0. I've also attached a picture of the project explorer as it may suggest something with Verison Control.
Evidently some of the colors are not as normal. I imported the project from a Gradle off of a shared GitHub Repo. Thanks!
You are in the build folder which contains generated files.
You changed that file, but then it was overwritten. You need to identify the source file and to make that change there if you want to have something persistent.
Running IntelliJ from C:\Program Files\JetBrains\IntelliJ IDEA 2021.3.1\bin: idea64.exe worked for me. Now files are being saved and it's not throwing this error. Navigate to your IntelliJ bin directory above and run IntelliJ from the executable. You may need to regenerate your short cut file to IntelliJ.

Eclipse not recognizing changes in code

A friend and I are working on a java project in Eclipse. Whenever we "ship" a new version we export it to a runnable jar.
It seems whenever we try to send the file back and forth (over google drive) to work on separate parts of it something gets messed up. This doesn't happen for him, but when I download the file from Google Drive, Eclipse does not recognize any change I make to the src.
It doesn't matter how many times I change the workspace, move/ rename the file, clean/ build the project. Nothing seems to be solving this problem. Any advice on why this is happening and how to fix it?
It would be infinitely better for the both of you if you looked into some kind of source control system, as opposed to a file sent through a file sharing service.
Sharing the source code in a JAR doesn't allow you to:
Keep a revision of known working code, in case something breaks
Reliably import the code
Keep track of changes (who did what to what file, etc)
Look into something that's suitable for sharing between users. GitHub and BitBucket both offer free Git hosting, which is a very popular source versioning tool.
Eclipse is probably building the new version of the runnable JAR in the project's output directory, which by default is something like %PROJECTDIR%/target. The new version of the JAR with your changes will be there, and you'll have to export them again to trade files back again. See also: How do I change a Java project's bin folder in Eclipse?
it is probably because it is not updating yours .class, try delete .class of "target" folder of your project, make clean (project - clean) and save again the changes
There are many steps where you can solved it,
Clean Project and Re-Build
Remove .metaData and .settings from Workspace
Clear cache
In my case, I have tried much more and I got to resolve it by removing Classes, test-classes folders if Its there in Target folder

Android : source not found [duplicate]

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.

Eclipse using wrong build while debugging

I am new to eclipse and java. The way I understand the directory structure is that you have source packages in src/ folder and they are built into the /build folder.
It was all working fine until recently. But today I tried debugging after creating a new class and it was throwing ClassNotFoundException when I do F11. On investigation, I found that it was using older versions of even the existing classes and not the new builds, and there was no .class file corresponding to my new class. I checked the build/ directory and it seems the builds are also old as it is showing yesterdays last modified time despite the fact that I have made changes today and tried to debug it. This problem is not limited to debugging as I exported the class into a jar file and it is still using yesterday's jar file. What could be the issue here? Is it not 'building' the classes? Have I messed up the default 'build' folder somewhere?
First you should check, that the "build automatically" feature is activated (menu "Project/Build automatically").
Next you should do a refresh of your whole project to tell eclipse to check for file changes that occured outside of the eclipse IDE.
If all that doesn't help, do a "Project/Clean.../clean all projects" inside eclipse.
I'd stop assuming and find out where Eclipse is putting your newer .class files. They can't be disappearing. Once you know that, compare it to the project set up you have and make sure that you know exactly where the .class files are going.

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