The problem in my case was that my project also needed native libraries and due to other errors, I have been fiddling with classpath. Re: Error: Could not find or load main class [ message #1263867 is a reply to message #1222641] Tue, 04 March 2014 21:03. Many reasons are there for this has to be happen. Thank you. That is a totally bizarre cause! You do not need to shut down Eclipse to change the, I, on the other hand, just shut down Eclipse (but did not edit. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. That error was eliminated. This problem wont come now if problem comes because of wrong class path. Error will go. -Run the test (it may ask to add Junit5 to build path) The cause not sure. It only happened to me after I added a new JVM. It may drive someone nuts when User1 can see the files, and can access to them, but the error still happens for User2. @gone - The reason that "." If user entry is deleted or any mistake then click on Restore Default Entries option in Run configurations -> class path. I couldn't find the matching point in "Reason #1" and "Reason #2" title didn't look close to my case (because I was sure there is no problem with classpath itself). Note here that class path does not include \com\company. You can try opening up the .jar in your favorite ZIP editor, and removing files from META-INF until all you have is your MANIFEST.MF. Just go to your Package Explorer and press F5, or for some laptops fn+F5. What does "Could not find or load main class" mean? Is there a more improved answer than this? I'm still working toward a solution. It was an exact example that followed the steps I made, and it worked for me too. But they are not in our class path. So I added the bin directory for the project.') I've seen it, so just want to share it here maybe someone else will need it. If you attempt rename a class by moving it, that will fail as well but the exception stacktrace will be different. Check the workspace error log (Windows-> Show View -> Error log). It will work. What might a pub named "the bull and last" likely be a reference to? On Windows put . Eclipse Could not find or load main class [message #1786819] Sun, 13 May 2018 07:32 Wayne George Messages: 2 Registered: May 2018 : . Please note that this is a "self-answer" question that is intended to be a generic reference Q&A for new Java users. 2) Then run the code and you can see it works fine if there is no syntactical errors. Was MS sim right? Project -> Clean will remove any existing class files and completely rebuild the project. I've a project named Helloworld which consist only 1 java file, Helloworld/src/com/firstpackage/Test.java (windows 10. intellij idea). Error: Could not find or load main class javafx.controls,javafx.fxml Caused by: java.lang.ClassNotFoundException: javafx.controls,javafx.fxml From the command prompt: java -version . Installation Error - Eclipse Error Code 13, Solve javac is not recognized as an internal or external command Error, How to Add or Import Jar in Eclipse Project, Solve java.lang.ClassNotFoundException: sun.jdbc.odbc.JdbcOdbcDriver Error. @StephenC I've tried to find a reason in your list by looking at "Reason" categories and their points. It was because I had Worked like a charm for me. Error: Could not find or load main class? Worked like a charm. Note: The only difference is that I didn't declare main to be public. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I used this command for compiling and it worked correctly: But this command did not work for me (I could not find or load the main class, qrcode): Finally I just added the ':' character at end of the classpath and the problem was solved: Could not find or load main class ?classpath. Finally, you can apparently run into this problem if there is a syntax error in the MANIFEST.MF file (see https://stackoverflow.com/a/67145190/139985). After this my project compiled with success. Delete metadata from work-space directory. I agree with @MuhammadGelbana, i deleted the .metadata and it blew my workspace. I agree with Nick Constantine. I had this problem on eclipse sts. Don't worry, you won't lose anything, but if you want to be extra careful, just back up the files from your java projects folder to somewhere safe. Reference: https://www.computingnotes.net/java/error-main-class-not-found-or-loaded/. I don't want to look like I'm trying to boost my own reputation points, so if someone can provide a better answer then please do so. [BUG] ClassNotFoundException RemoteTestRunner With very specific project configuration, JUnit5 does not work with Eclipse 2020-06, Sample project - https://github.com/AndreBritoKD/SimpleQaurkusGradleProject. It works with ; for Windows and : for Unix: Steve C's answer covers the possible cases nicely, but sometimes to determine whether the class could not be found or loaded might not be that easy. Trying to run a java program in console will give a could not find or load main class error, (Error) Could not find or load main class, Eclipse Error: Could not find or load main class, Eclipse on OS X El Capitan Error: Could not find or load main class. What worked for me: For more details, please refer to the official documentation for the java command for the Java release that you are using. Have Googled extensively on this error, but I can't seem to fix the problem. Import the project again, but selected copy to work-space option. :). If we recompile project then all .class files will again created in bin folder. Then worked! yep. I had to remove the .jar file from Project > Properties > Java Build Path > Libraries. Douglas. "Braces for something" - is the phrase "brace for" usually positive? It sounds like the problem was that you had a incorrect classpath due to a broken "reference" in your project in your IDE. I hope above solutions will fixError could not find or load main class in Eclipse. "Debug certificate expired" error in Eclipse Android plugins, Eclipse - Error: Main method not found in class projectOne, please define the main method as: public static void main(String[] args). Error: Could not find or load the main class lastfmhistoryguis.InputPanel I've tried building the project from: Project>Build Project But nothing happened. If you do that, then you are not using the default classpath. When class loader is unable to load the main class of our application then this error will come. After creating the missing folder everything works. As an error setting the classpath using ; is not thrown then this can be a difficult to discover if coming from Windows to Mac. And indeed, the "" in the message will be the fully qualified class name that java is looking for. And I tried to run also with the same extension: When I removed the .java and rewrote the command like java HelloWorld, the program ran perfectly. Purpose of some "mounting points" on a suspension fork? After some background tasks you will be directed to your main project directory. Many of these parts adopt various caching strategies in order to make the IDE as a whole responsive. Can be resolved by updating your project. project properties -> removing previously missing jars helped fix it. "Could not find or load main class" What does this mean? I'm able to run the program from the command line by navigating to /bin/ in the project's folder that's in the workspace and typing java Conversion. There was a red flag in there. Sure you can say "you should read everything described in the post" but it seems to me your reason list can be improved. Use java -Xdiag (since JDK7). Because I installed a newer JRE version and that won't allow other previous versions to run on it. Where can one find the aluminum anode rod that replaces a magnesium anode rod? I had a problem where Eclipse threw that error because I had manually deleted some *.class files. How can one refute this argument that claims to do away with omniscience as a divine attribute? I like this solution much better than fiddling around with this or that configuration option. If because of bootstrap entries then Click on Bootstrap entries -> Advanced -> then select Add library -> JRE system library -> OK. Please mention in comments if the solution was helpful. In my project I have the src folder and bin folder at the root. Any suggestions? How to connect two wildly different power sources? I've updated my answer to try to address that confusion. I have tried that but unfortunately no, it does not work. for me it happen on project that worked before so i fix it by "rebuild project". Not the answer you're looking for? You are depending on the CLASSPATH environment variable being unset, or having a value that is consistent with ".". To understand when it works, and when it doesn't work, read the top-voted answer. Eclipse error "Could not find or load main class". You could simply delete $yourproject/.classpath , $yourproject/.project , and $yourworkspace/.metadata. The java classpath handling has a certain logic, but I sure wouldn't have designed it that way. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I'm still working toward a solution. After adding jdk-8, remove the jdk-13 from Preferences. Manga where the main character is kicked out of a country and the "spirits" leave too, Closed form for a look-alike Fibonacci sequence. For me it is too far-reaching change, because I lost the whole workspace configuration. Hi! For the main class to load correctly, the JVM needs to find: (Note: the JLS and JVM specifications allow some scope for a JVM to load classes "lazily", and this can affect when a classloader exception is thrown.). This worked, thank you. Addition: I have noticed that this bug occurs when you have many projects in a work space and some of them is configured wrong(red exclamation mark appears). This worked for me as well but what is meant by classpath getting over the limit? 1 ) Clean the Project I thought that I was somehow setting my classpath incorrectly, but the problem was that I typed: I thought the meaning of fully qualified meant to include the full path name instead of the full package name. -U,--update-snapshots Forces a check for missing releases and updated snapshots on remote repositories, this worked like a charm for me too after struggling for days to get it work, loved this: Delete the metadata folder inside your workspace I was able to fix it for myself by making a new workspace, This fixed it for me. For example, consider: This is because the running user (User2) does not have access to dir1, dir2, or javalibs or dir3. So all those old files I have become useless in a way. What's the meaning of "topothesia" by Cicero? All Rights Reserved. There should be no more errors on your project now. If default class path is not set then click on user entries -> Add projects -> select your project name -> click ok. Now run it. In this article, I'll share three useful tips to solve the "could not find or load main class error" in Eclipse. If not then just remove the package declaration from above code and it will run fine. . And the missing superclass problem is a very unusual subcase. rev2023.6.12.43489. See this example of generating a class file of a simple code: The project name is 10.12.12: Project. I guess it allows you to run without ever building. It will output various things about class loading, and this may offer you clues as to what the real problem is. My class is in the (default package), if that helps at all. Home Language IDEs Java Development Tools (JDT) Error: Could not find or load main class Caused by: java.lang.ClassNotFoundException: (After Java 16 update, this error for all the Project ) Show: Today's Messages :: Show Polls :: Message Navigator Goto Forum: -=] Back to Top [=- [ Syndicate this forum (XML) ] [ ] Yes, it works in many cases, but it won't in others. Methodology for Reconciling "all models are wrong " with Pursuit of a "Truer" Model? (The system classes are located automatically, and you rarely need to concern yourself with this.) How do we "remove all references to the class"? There are TWO because the error says "Could not FIND or LOAD main class". Or is it neutral in this case? Should I insulate water pipes in exterior walls? So I added the bin directory for the project. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I think it's good to summarize my final solution in short so that in the future anybody can directly look into the two commands and are good to proceed further. I had this problem twice in Eclipse. You may have unknowingly made eclipse regenerate those files by introducing errors. That is probably because you have actually set the %CLASSPATH% environment variable somewhere. I was getting the exception despite having correct entry point configured in pom.xml.In my case this error was occurring because I forgot to mention "string[args]" in main method arguments,ie I had written - public static void main() --- INCORRECT Instead Of public static void main (String args[]) -- CORRECT, i found signature of main class was deviated from psvm(Strings[] args) to psvm(String args),after corrected its resolved. Now recompile the project. Why did banks give out subprime mortgages leading up to the 2007 financial crisis to begin with? Hence, I have decided to jot down my experience with a couple of more tricks from the past. It was a referenced library that I moved, and it gave me the: Could not find or load main class xxx Linux. Sign in Hello Anonymous, did you put the class inside com/hello directory? Would easy tissue grafts and organ cloning cure aging? Select my project as the resource and ensure .classpath and .project files are selected. You may run into this problem if you have invalid or incorrect signatures in META-INF/*.SF. I did have Jar file (last.fm-bindings-0.1.1.jar) that was in my .classpath file that was in C:\Users\Chris\Downloads folder on my laptop hence it wasn't included in the git tree which I recently brought into the project folder and committed ,but I'm not sure whether I have done it right. 4- Delete the jar file from there (I see a red mark beside it). Thanks a zillion times over :), @lake it worked for me,can you please explain how a unused jar leads to this kind of problem, Wish I could give you more credits. Making statements based on opinion; back them up with references or personal experience. Eclipse turns me off from programming in Java. I'm on Windows 7 64-bit. static void main(String[] args) Before project name red exclamation mark will appear. SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder", Eclipse Plugin Get Code from Current Open File. Who's the alien in the Mel and Kim Christmas song? What might a pub named "the bull and last" likely be a reference to? I already had build automatically set, but forcing STS to rebuild it fixed it. In the other hand, they could also say "The file was found but could not be loaded" at that point, we would promptly focus on dependencies instead of losing half a day researching and testing things to understand. Here we can see .class file of main in bin. A better idea is to learn / understand what caused the problem and implement the correct solution. Most Java programs are not that simple. is not in $PATH by default is that it is a security trap. Yes, it is checked. Java Error: Could not find or load main class Error. All answers here are directed towards Windows users it seems. There you type the following command line: Let's say your class is called CommandLine.class, and the code looks like this: Then you should cd to the src folder and the command you need to run would look like this: And the output on the command line would be: All right, there are many answers already, but no one mentioned the case where file permissions can be the culprit. Find centralized, trusted content and collaborate around the technologies you use most. For me the following steps solved the problem. Delete ".metadata" folder in your work-space. I noticed that someone said I have to create an entire new WORKSHOP! See "Additional Notes #1" of my Answer. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If that is the case, you should just select Project > Clean. Solution: If user entry is deleted or any mistake then click on Restore Default Entries option in Run configurations -> class path. That would be a Java syntax error. And indeed, the "." in the message will be the fully qualified class name that java is looking for. And it worked. It failed and produced a wrong error message. Eclipse "Error: Could not find or load main class" (62 answers) Closed 9 years ago. Open the file and read it and you'll get an idea of what they do. What bread dough is quick to prepare and requires no kneading or much skill? I have a main method in a package in one of my projects. EDIT: Then rebuild your project. It seems that the class is not compiled by Eclipse. 1) I've checked run configurations. Registered: March 2014. 3. I removed the jar file from the Libraries and it worked. The .class file does not exist directly in my output folder - it's located in a subfolder called bin. Never faced such type of issue before. Your email address will not be published. Thanks. Go to Window -> Preferences -> Add -> next and find your jvm folder (e.g. 2 ) Enable build automatically Option Does a "Find in project" feature exist in Eclipse IDE? Remove existing run configuration and new one. I had my workspace in my personal folder and its name was in Greek, so it didn't work. If camel-spring is not included, this error will be reported. tryn to setup javafx in the eclipse, but cant seem to get it to work. There are three alternative syntaxes for the launching Java programs using the java command. My java installations were unbound, due to central company updates. Obviously it lacks details of any specific problem. Then you need to load the program. What proportion of parenting time makes someone a "primary parent"? is on the classpath) than by judgement (i.e. When I run in eclipse I get this error: Error: Could not find or load main class net.minecraftforge.legacydev.MainClient Caused by: java.lang.ClassNotFoundException: net.minecraftforge.legacydev.MainClient (It is not mandatory. Tnanks, your answer help me to look that i used Main with Uppercase. If you create a java class with public static void main(String[] args), Eclipse will run that main method for you by right clicking on the file itself, or on the file in the project explorer, then choosing: Once you do this, Eclipse stores information about your class, so you can easily run the class again from the Run As menu (Green Play Button on the toolbar) or from the Run Configurations dialog. In Run->Run Configurations, I've checked that the Main class is com.ant.car. Could not find or load main class application.Main Caused by: java.lang.ClassNotFoundException: application.Main while trying to use JavaFX in Eclipse Run then run configurations In Main, choose the correct Project and Main class names For cleaning option click on project -> clean. This was translated into the following string in the eclipse.ini and config.ini. Do characters suffer fall damage in the Astral Plane? If you erase the invalid signature, you are in infecting your application with the malware!) Find centralized, trusted content and collaborate around the technologies you use most. Right click, Run As -> Spring Boot App). After the update with java 16 and the new version of Eclipse 2021 03, So you have installed Java 16 support from marketplace entry. I have a project in eclipse on my laptop that I pushed to Git https://github.com/chrisbramm/LastFM-History-Graph.git, It works fully on my laptop and runs/builds without a problem but on my desktop it doesn't Eclipse gives the error, Error: Could not find or load the main class lastfmhistoryguis.InputPanel. Let's not extend this discussion further :) I changed my statement to "not fully discussed in the accepted answer" and hope you feel better. Instead: Similar thing happened to me few times, the only way I knew to fix this was to remove the metadata folder. Sometimes our main class will be related to some other classes which are present in other libraries. Where in this example the package is com.test and a lib folder is also to be included on classpath. Hello Anonymous, can you provide more detial? is on the classpath). Or else if any mistake is in user entry or Bootstrap entries in class path then also eclipse cant find .class file of main class. Under the bin directory, "java Test" works fine in the command line. in eclipse click on Windows > Preferences > Java > Installed Jres > click on Jre and edit after that look into jar list make sure none is of jdk or corrupted , I had the same problem with correct .classpath file, and soon found actually it's not the .classpath file counted (after I fixed this issue, I replace the workable .classpath file with the original one, the project still worked, which means the .classpath file was not the case). (I got this error after removing AWS ToolKit). (What you mean is that the file containing the compiled class is called "CommandLine.class" ). Then change the current directory of the terminal to the root directory of the project: If you don't have any package on your source code name maybe you are wrong with the wrong command. Rather than posting a "me, too" as an answer, I'd recommend getting enough reputation (you only need 50) to post comments and confirming that a particular approach worked for you in a comment. Eclipse was installed inside that folder and therefore the ".eclipse/", ".p2/" were there as well. Well occasionally send you account related emails. Someone else mentioned this option. This is because you are executing the compiled version of your .java. There lots of things to check, and it is easy to miss something. This worked for me when I faced this problem second time: Add Library. I'll update my answer to cover that case. -Try to play with the dependencies, by removing some at random and do a Gradle refresh and the rests run again. I ran into this error today because I set up a hello world program and then cut and pasted a new program into the same file. Close or Refresh the Eclipse/ STS Eclipse. Weak convergence related to Hermite polynomial? This error may come due to missing libraries or jars. Normally if a class is not on the classpath, the error thrown indicates as such. The fully qualified name of my main class is: So I cd back to the root project directory: This answer is for rescuing newbie Java programmers from the frustration caused by a common mistake. Type "cd (folder name)" in the stored drive and compile it. A simple refresh did. I think .class files are deleted/missing from JavaProject/bin folder. Thanks, deleting existing run configuration solved the problem. after I move the project to git. (openjdk version "11.0.9.1" 2020-11-04). In your classpath you should therefore (and probably in general if you're gonna bundle JARS with your project), use relative pathing: I did all the things mentioned above, but none of them worked for me, I faced similar problem in my maven webapp project after spending nearly one hour , I found a solution which worked for me .I typed the following maven command and It worked. I still got Error: Could not find or load main class Temp could anybody help! How to specify the Main Class name and provide arguments to my Java program? Connect and share knowledge within a single location that is structured and easy to search. Linux does, though. While it is conventional / normal to make an "entry point" class. The "class could not be found / load" error should be gone. instead of I finally got that to work by putting '%JAVA_HOME%/bin;' at the front of the path environment variable instead of at the end. Same Problem occur with me.I went to Project > Properties > Java BuildPath. I found the answer on going to the Run menu, Run Configurations and browsing to find the Project and Main class. :D, Please understand what >>I<< meant. Similarly if you use a decent Java build tool, the tool will run javac in a way that will detect the problem. First of all, you need to understand the correct way to launch a program using the java (or javaw) command. Right click on your project - Properties then Libraries tab. Not the answer you're looking for? Deleting the bin folder and doing a "project > clean" and build has already been suggested in other answers. In eclipse if we run application Run as java program then eclipse will give default path as the User entries in class path in Run configurations. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If you subsequently MOVE the java class (manually, or however), then again choose. See all the Run it Error may not come. How could I have made my question any more specific? Check if the .class file exists in your output folder.To know your output folder, Check if the HelloWorld class is in src folder or not.Right Click on. Not really sure what else to do. Eventually I tried this and it worked perfectly: menu Project -> Properties How to get rid of black substance in render? Finally, if your compile used a "-cp" argument, then you need an equivalent on when you run. There In order of export , I moved up my java/main to the top priority. Classes are located in the directory structure beneath that root, by mapping the fully qualified name to a pathname. this could cause of jdk libraries if you had imported into jre, this happen to me , so check installed jre jars. Methodology for Reconciling "all models are wrong " with Pursuit of a "Truer" Model? 2) I've checked build path. ('Add where Eclipse usually put the *.class for the projects, which is in bin. The problem started when I changed the name of the project. Share. then refresh your project, it will resolve your issue. If you see any of the jar's imported is corrupted, remove the corresponding repository folder and re-import again. (I think that the error message is correct. which (confusingly) looks like a file pathname, but isn't one. Do characters suffer fall damage in the Astral Plane? You'll have to import all your projects again. Also you can set it "one time" with set CLASSPATH=%CLASSPATH%;.. Then you should either fix your existing configuration or add a new one in the following way: Open the Classpath tab, click on the Advanced button, and then add bin folder of your project. That's the only thing in Eclipse's console when I try to run the project. If you want to do something constructive, submit a patch. As shown below. (What does, This worked for me when I tried to run a simple program from command line, Finally fixed the issue for unix .. thanks (works with :). Is it okay/safe to load a circuit breaker to 90% of its amperage rating? Further reading: How to Fix java.lang.UnsupportedClassVersionError I also had an exclamation mark next to my Project folder name. Copyright Eclipse Foundation. In my src folder, I can only see HelloWorld.java and no .class file. The problem was obscured by the error because it always complains about the main class not found, similar to the annoying popup below: "Error: Could not find or load main class Main". You really need to do this from the src folder. Go into the eclipse external tools configurations, open the entry for the ant file you are running, then go to the JRE tab, and select "Separate JRE", also making sure your new jre is correctly listed in the Installed JREs.for me, this took care of it. Select "Object" if your file will contain a top-level object instead of a top-level class. (, How to fix maven dependency search not working in Eclipse? @StephenC Yes, your answer is more complete (and of course, +1), but this particular answer had the word "package" in it, which allowed me to find what I needed fast. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. The other problem is that your instruction to "cd to the source directory" only works if you compiled the code >>into<< the source directory tree. Here our project will compile and all class files will be created in bin folder but path is not correctly specified. Reasons why Java cannot find the class. (left rear side, 2 eyelets). Also, consider possible problems caused by copying and pasting invisible or non-ASCII characters from websites, documents and so on. None of these worked for me. Thanks for contributing an answer to Stack Overflow! Since it's a Maven project, all I did is: This problem is also caused when you have special characters in your workspace path. The problem was that >>you<< narrowed in on the wrong clause. I tried it out on three different machines, you can try that out as well. This only works in simple cases. The fact that it's received more than 25,000 views is an indication that many people suffer from this problem. If I right click on the project, I select Build->Build Path, and under the Libraries tab I make sure there are no missing folders with red Xs next to them. How to land with no propulsion? from the new location, Eclipse will run the original stored configuration, attempt to invoke this class from its original location, which causes this error. i have execute the program and no errors in program but program is run then get the error is could not load main class. @GKFX - That's what I mean. Once I cd-ed above and ran with the package name included in the command line it worked. Now all is back to working. Tried above mentioned steps to resolved issue. This problem occurred for me when I deleted a ".jar" file from Eclipse project by right clicking on it and hitting "delete" (not from "Build path"). I've set the PATH variables on this computer to JRE6, JRE7 and JDK 1.7.0 even though these aren't set on my laptop. This prints out a nice stacktrace which provides a hint to what the message Could not find or load main class message means. - that doesn't sound like a very smart thing to do. The java command was not able to find the class. error: could not find or load main class , "Error: Could not find or load main class ", Java could not find or load main class error. Does it make sense to study linguistics in order to research written communication? Sandra Lail. 1 - There are some other syntaxes which are described near the end of this answer. on it), "cd" will have no effect. I had to, Examples (of offending compilers) please. It was many things but all related to the same problem. I just deleted that reference, added it again, and it worked fine again. Now, in a file explorer, go into $yourworkspace/.metadata. You just need to delete Run Configuration file and restart STS and run command -mvn clean install and try to restart the service. It will blow up your entire workspace though. In Boot Dashboard > left click in your project > Open Config > fill the "Main Type" with your main application. Understanding residence question in UK Visa application, Use a file explorer on your operating system to navigate to your workspace (In my case, I'm on Windows so I used Windows Explorer). This was exactly my problem. to take the current folder as reference for classpath. And make sure that all dependent libraries should be there even if we are not using them. (2) If first solution is not working then it means the jar you are pointing out to your project is taking the path of your local Maven repo which is not getting updated to your project so better you check the jar from that local maven repo and copy it paste it into new project simply or just download it from any site and configure it into your build path. Can't find words to thank you. In the Classpath tab: Select Advanced Understanding residence question in UK Visa application, Create MD5 within a pipe without changing the data stream. Does it make sense to study linguistics in order to research written communication? In "Forrest Gump", why did Jenny do this thing in this scene? I've run the program from a Windows 10 batch file, and put the .jar name in a variable (called with "-cp %jarname%;lib*"). To resolve this issue right click on project -> build path -> configure build path -> Libraries. It is a wildcard syntax. However it is still possible for this exception to occur, if you do things behind the back of the IDE. This answer makes a whole load of assumptions. The "Could not find or load main class" error occurs when the JVM fails to load the main class. I tried all the answers but finally what worked for me was deleting the project from eclipse workspace and importing it again. This solution works more by luck (i.e. It is sad to see that. Click on apply and execute. could you please say what specs, versions, OS's you are using? "Murder laws are governed by the states, [not the federal government]." Remove all boilerplate from the example that is irrelevant for the problem? Now run it error may go. Assume you are in the directory where your Java file and external dependencies (JAR files) exist. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. What's the meaning of "topothesia" by Cicero? or look in the ".project" file (in /workspace/yourProjectName/.project) the section "buildSpec" should not be empty. It all had to do with the home folder and a special char in it. nevertheless, if it runs in your system then it is probably something with my installation, EDIT 2: Try going to project properties > Java Build Path > Order And Export tab > select all (or try to play with check boxes there). sdsd, Please do observe the colon (Unix) / comma (Windows) after all the dependency JAR files end, At the end, observe the main class name without any extension (no .class or .java), Firstly, I have come across with multiple. see. Chances are, that I don't need to introduce 10+ dependencies to reproduce the issue. In case you are struggling to solve your program errors or need java assignment help then you can visit www.geeksprogramming.com. -Run the test (it may ask to add Junit5 to build path) "); } }Output (console):Error: no se ha encontrado o cargado la clase principal SuperPowerCausado por: java.lang.ClassNotFoundException: SuperPowerHello, Javin!I am receiving this error message when I try to run my program. I had the same issue and solved it using: The Problem was that i made my maven project available to github. I am not trying to convince you. yes, sometime that works, check if you clicked the "Build Automatically" option as well, this means it will automatically build your project if there is a change. Find centralized, trusted content and collaborate around the technologies you use most. Don't understand why it can't use the Current Working Directory by default. (After Java 16 update, this error for all the Project ). Connect and share knowledge within a single location that is structured and easy to search. ), Wow! Learn Java and Programming through articles, code examples, and tutorials for developers of all levels. Reason behind this: The compiler had issues linking the libraries to the project. Does Grignard reagent on reaction with PbCl2 give PbR4 and not PbR2? Strangely, now every download project runs clean without any problems of 'could not find or load main class' , perhaps the problem in my case was related to the workspace's metadata? It still says, "Could not find or load main class HelloWorld". Check the bin folder, it should be empty. These are generally immune from this particular exception, because the IDE uses its own mechanisms to construct the runtime classpath, identify the main class and create the java command line. To learn more, see our tips on writing great answers. VERY CAREFUL: This will unbind your project from the workspace. Does there exist a BIOS emulator for UEFI? Why is there software that doesn't support certain platforms? It won't if they are not. Then also eclipse cant find main class. The . Step 5: Save your file by hitting ctrl + s. Step 6: For safe side just close the project once and reopen it. I tried to modify the classpath configurations in Eclipse but with no success. *.java - This is the Java class file which has main method. Messages: 1. So why might it be unable to find the class? Still not refreshed your projects automatically, just restart your STS and check. For instance, it can point you to other classes used by the main class that could not be found and prevented the main class to be loaded. I'm convinced that Java is sponsored by Keyboard manufacturers!! But nothing happened. You will get that error if you call it using: If your classes are in packages then you have to cd to the root directory of your project and run using the fully qualified name of the class (packageName.MainClassName). The second likely cause is that the class name is correct, but that the java command cannot find the class. (, How to make an executable JAR file in Eclipse? In this tutorial you will learn about the error could not find or load main class in eclipse and the ways that could solve this error. This just happened to me today after updating my JRE. This advice may or may not help. Does the policy change for AI-generated content affect users who (want to) Eclipse Error: Could not find or load main class, Cannot load or find main class, works in command line but not in IDE's, Eclipse Error - "Could Not Find Or Load Main Class", main Class won't load on a different computer, Error: Could not find or load main class in Eclipse Kepler, Eclipse does not compile java files (already tried the answer to the possible duplicate), Error: Could not find or load main class Start, Error: Could not find or load main class in Eclipse, Could not find or load main class Eclipse, eclipse error: could not find or load main class for project, Eclipse: Could not find or load main class. 16.6k Posted October 6, 2014 Yeah, I have no idea what's wrong. Occasionally when we run a Java program, we might see "Could not find or load main class." It's easy to guess the reason: The JVM failed to find the main class and gave this error. as the classpath by default, not as part of the classpath by default. Incorrectly specified classpath of the application. If any problem with bin folder clean the project. Add where Eclipse usually put the *.class for the projects, which is in bin. The problem is that this solution only works for Java classes declared in the default package with no JAR file dependencies. I've tried with Eclipse SDK and Oracle JDK as well and still does not work @StephenC and EduardoDennis, It was that here too, there was a jar missing, that jar contained an interface that the main class depended on to be instantiated. To give a concrete example, supposing that: The classpath needs to include all of the other (non-system) classes that your application depends on. 2. And there are other ways to achieve this. Raedwald, do you even forums? Thanks for contributing an answer to Stack Overflow! To subscribe to this RSS feed, copy and paste this URL into your RSS reader. If it runs, you will at least understand that the problem is not because of run configuration or eclipse but the class, your main class extends. I was unable to solve this problem with the solutions stated here (although the answer stated has, no doubt, cleared my concepts). check project properties (in the "package explorer", right click on the project, select "properties"), there the second section is "Builders", and it should hold the default "Java Builder". Error: Could not find or load main class Files\Eclipse Caused by: java.lang.ClassNotFoundException: Files\Eclipse 557 How to deal with "java.lang.OutOfMemoryError: Java heap space" error? I deleted. Sometimes what might be causing the issue has nothing to do with the main class, and I had to find this out the hard way. It worked for me: Try adding your external libs/jars one after each other. Then you should check, is there anything else, which is causing build ti fail. Hi, I'm experiencing a very strange behavior when I try to run a simple Junit test. Why does Tony Stark always call Captain America by his last name? Thank you, @Akeme, Eclipse Error: Could not find or load main class [duplicate], Eclipse "Error: Could not find or load main class", How to keep your new tool from gathering dust, Chatting with Apple at WWDC: Macros in Swift and the new visionOS, We are graduating the updated button styling for vote arrows, Statement from SO: June 5, 2023 Moderator Action. Mostly this happens, because Eclipse cleans the .class files, but don't build them again. Choose "Jar file" and Next. Before, make sure Gradle or maven is installed in your OS. (, How to fix Unsupported major.minor version 52.0 error in Eclipse? With JDK 8 many times it happens that the class file is present in the same folder, but the java command expects classpath and for this reason we add -cp . that's because you guys created the class one time with the main method & after that may be you have been deleted that form or workplace & still some of the files exist ,i will suggest you to create that form or workspace again & then delete it by clicking on it completely,then after that if you created the some class like Runner class try to run it again. In our project, we are using Maven as build tool and my main class extends a class, which is on the class path but its scope was test, while the main class is not under the test package. The numerical solution cannot be obtained by solving the Trigonometric functions equation under known conditions? In this situation is there any way to tell exactly which dependency class is failing to load? Run your project like you normally would. (And even then, not all of the time.) The people who might concievably act on your complaints won't notice it. Right click on my main project directory. Nice one @Razavi. I try this and I also need to "close project" and "open project" to do the trick. where is a command line option (starting with a "-" character), is a fully qualified Java class name, and is an arbitrary command line argument that gets passed to your application. Any help would be appreciated! what is difference between na-nimittaggh and animitta? How to optimize the two tangents of a circle by passing through a point outside the circle and calculate the sine value of the angle? I've mistakenly put an extra space at the end of the jarname, and it caused the error. It is actually executing the .class file. Cleaning the project, build automatically is already checked, deleting .metadata, etc. @EricSwanson same for me I had to remove the project from eclipse, remove the .classpath and meta project directories, remove build directory and import the gradle project back into eclipse. Here is an example of what a java command should look like: The above is going to cause the java command to do the following: When you get the message "Could not find or load main class ", that means that the first step has failed. I also faced similar errors while testing a Java MongoDB JDBC connection. If not gone check bin folder after cleaning again if all the .class files are deleted or not. What proportion of parenting time makes someone a "primary parent"? I've written a basic java program in Eclipse Juno, as follows: After clicking Run, I get: "Error: Could not find or load main class HelloWorld". By refreshing it, you put them both on the same page. Windows (tested with Windows 7) doesn't accept special characters (like ) in class and package names. @code4u - Please see the first comment. Debug is better way to know about it. In short, if you get this problem in an IDE, check for things like stale IDE state, broken project references or broken launcher configurations. Where can one find the aluminum anode rod that replaces a magnesium anode rod? Eclipse "Error: Could not find or load main class", https://github.com/chrisbramm/LastFM-History-Graph.git, How to keep your new tool from gathering dust, Chatting with Apple at WWDC: Macros in Swift and the new visionOS, We are graduating the updated button styling for vote arrows, Statement from SO: June 5, 2023 Moderator Action. The Trigonometric functions equation under known conditions extra space at the end of this answer very unusual subcase tool run... *.java - this is because you are eclipse could not find or load main class classnotfoundexception the compiled class not! Suffer from this problem file from the src folder project available to GitHub Notes. Pbcl2 give PbR4 and not PbR2 have become useless in a way our project will and. Black substance in render 'll update my answer to cover that case if that helps at all personal experience rebuild! Declare main to be included on classpath would n't have designed it that way execute the program and no in... Directory structure beneath that root, by removing some at random and do a Gradle and. Random and do a Gradle refresh and the rests run again because cleans... The.class files are deleted or not which has main method a referenced library that I n't. Understand what > > I < < narrowed in on the wrong clause deleted some * for! All dependent libraries should be no more errors on your complaints wo n't allow other previous versions run! Is Could not find or load main class me the: Could not find or load class. Instead of a top-level Object instead of a `` Truer '' Model deleted some * for... Be reported automatically option does a `` -cp '' argument, then you should just select project > Properties to... Your java file, Helloworld/src/com/firstpackage/Test.java ( windows 10. intellij idea ) > > you < < narrowed on! I knew to fix this was translated into the following String in the Plane! All had to eclipse could not find or load main class classnotfoundexception the package is com.test and a special char in it still says ``... Cleaning the project. ' java ( or javaw ) command configuration solved problem... Problem where Eclipse usually put the *.class for the project name is correct class Temp Could anybody help,... Files and completely rebuild the project again, and $ yourworkspace/.metadata put them both the. Then this error after removing AWS ToolKit ) but forcing STS to rebuild it fixed it this! A red mark beside it ) you want to do away with omniscience as a attribute. If your compile used a `` project > Properties How to fix maven dependency search not working Eclipse! Folder but path is not included, this happen to me today after updating my JRE package one. Reach developers & technologists worldwide to setup javafx in the Astral Plane JRE, this error, but selected to! Way that will fail as well the problem.eclipse/ '', Eclipse get. Way I knew to fix maven dependency search not working in Eclipse see any of IDE. The.class files will again created in bin folder automatically option does a `` primary parent '' and. Completely rebuild the project and main class '' I faced this problem wont now. The.class files 've tried to find the project. ' decent java build -... Anode rod that replaces a magnesium anode rod that replaces a magnesium rod. '' on a suspension fork, this error, but is n't.. Which is in the eclipse.ini and config.ini for the projects, which in! Technologies you use most this happen to me eclipse could not find or load main class classnotfoundexception after updating my JRE it worked for me was deleting project! N'T notice it please understand what > > you < < narrowed on. Or however ), ``.p2/ '' were there as well judgement ( i.e projects again because have. ( what you mean is that I used main with Uppercase folder - it received! Error log ) '' - is the phrase `` brace for '' usually positive back of jar... For all the answers but finally what worked for me it happen on project - Properties then libraries tab share! No idea what & # x27 ; t seem to get rid of black substance in?. You want to do something constructive, submit a patch in Run- > run configurations - > build... Automatically, and it caused the problem started when I changed the name of the jarname, it. Is looking for experiencing a very strange behavior when I try to restart the service that reference, added again!, & quot ; and next I hope above solutions will fixError Could find. Many things but all related to the 2007 financial crisis to begin with that it is too far-reaching,! User entry is deleted or any mistake then click on project that worked before so fix! There any way to launch a program using the java command was able. Mortgages leading up to the top priority `` open project '' feature exist in Eclipse in. After updating my JRE reason behind this: the problem String [ ] args ) before project name exclamation... But path is not correctly specified Properties How to get it to work with omniscience as a divine?... Understand what > > I < < narrowed in on the same issue and contact its maintainers and the run! Followed the steps I made my maven project available to GitHub by introducing.. Eclipse workspace and importing it again 've tried to modify the classpath default! Load '' error should be gone solutions will fixError Could not find load! Inside com/hello directory Yeah, I have execute the program and no errors in program but program is run get. Of a simple Junit test ( of offending compilers ) please a reason in your.... Trigonometric functions equation under known conditions problem started when I try to address that confusion they do the corresponding folder. % classpath % environment variable being unset, or for some laptops fn+F5 Could., 2014 Yeah, I 've a project named Helloworld which consist only 1 java file and it. You had imported into JRE, this happen to me after I added the bin folder clean the project.... Test ( it may ask to add Junit5 to build path ) the section buildSpec..., and it blew my workspace class '' your file will contain a top-level class import all projects... Jdbc connection the steps I made my question any more specific occur with me.I went to >. Using them to reproduce the issue qualified class name and provide arguments to my java installations were unbound due! The missing superclass problem is that the error says `` Could not be empty java command can be! (, How to get it to work you clues as to what the message Could not find load. Used main with Uppercase > class path does not work libraries and it will resolve your issue anode! It should be there even if we recompile project then all.class files will be reported had exclamation. I just deleted that reference, added it again eclipse could not find or load main class classnotfoundexception but cant seem to get to... Section `` buildSpec '' should not be obtained by solving the Trigonometric equation. And check red mark beside it ), `` Could not find or main. In Eclipse kneading or much skill this. % classpath % environment variable unset! Will appear and no errors in program but program is run then get the error message is correct application. Use the Current working directory by default is that I made my maven project to... Which has main method answer on going to the same page '' on a suspension fork under BY-SA! Working directory by default, not all of the classpath environment variable somewhere erase the invalid,! What you mean is that the file and read it and you 'll have import! ; works fine if there is no syntactical errors only see HelloWorld.java and.class. Can one refute this argument that claims to do something constructive, submit a patch by and... That java is looking for works, and it worked perfectly: menu project - clean! Referenced library that I made, and it worked perfectly: menu project - > How! Fix Unsupported major.minor version 52.0 error in Eclipse & quot ; and next be related to some other which... My JRE the malware! ; back them up with references or personal experience what is meant by getting! Is deleted or not wrong class path does not exist directly in my folder. Central company updates it does n't support certain platforms your RSS reader ''! Quick to prepare and requires no kneading or much skill missing jars helped fix it it. Help me to look that I used main with Uppercase > java BuildPath file and read and... Government ]. said I have execute the program and no.class file does not work then.class! A suspension fork Object & quot ; and next by Cicero you see... Damage in the command line see.class file of a `` primary parent '' many things all! That I do n't need to understand when it does n't accept special characters like... Reference, added it again next to my java installations were unbound, due to missing or. Already checked, deleting.metadata, etc on this error will come open ''! Fixed it to your package Explorer and press F5, or however,... Name to a pathname output various things about class loading, and this may offer clues... Executable jar file & quot ; jar file in Eclipse linguistics in order of export, I 'm convinced java. That java is sponsored by Keyboard manufacturers! the IDE private knowledge with coworkers Reach... Your answer help me to look that I do n't need to `` project. $ yourproject/.project, and it worked '' in the ( default package ), you. The *.class for the problem and implement the correct solution might a pub named `` the and...