[screen shot of project and error message in eclipse ide][1]
i have already made and tested a snake game in java.A siple GUI development using swing.It was running pretty fine
But when i went to create a runnable jar file i found that the classes were included in the java default package.So what i did was make a new project and copy the used resources and class.But this is the error message that shows up.
As you'll can see main is already defined in the Game play class(reffer to the image) ,hence i coudlnt think of a reason why this error message would show.
I tried changing the workspace as well but in vain,and furthermore now on running the application(with warnings ofcourse) the used resourses woulnot load!
Totally in a mess!!
could the community kindly help me fix it?
if the image is not visible try this link
https://i.stack.imgur.com/NF34x.jpg
Did you remember to include a package declaration? Remember, in order to run a java program that is inside of a package, you must include a package declaration.
I have a project in intellij and when I created my packages I made a mistake because they all start in capital letter, for example my previous package name was "Main" then I changed it to "main" and I did it to all of my packages.
error: package com.myproject.thesis.main does not exist import
com.myproject.thesis.main.Main;
but the "main" package and "Main" class does exist and already imported on the class that needs it. Also what should I name the package where I put my main class?
While it may not help in this case, a general thing to try when "My code compiles and runs, but IDEA is really confused about the symbols in my project" is to go into the "File" menu and choose "Invalidate Caches / Restart". I've rarely used it, and it doesn't always help, but every once in a while it fixes IDEA's confusion.
See also the IntelliJ IDEA help on Cleaning System Cache.
You need to edit configuration. From IntelliJ Run menu choose Edit Configurations. On the configuration window change the package name of Main class.
I hope this helps.
Try changing the packages to something else first. e.g. coma.myprojecta.thesisa.maina and get that to work. Then change it back to com.myproject.thesis.main. I think IntelliJ might be having problems with the change in case. If you change it something totally different and then back it IntelliJ should realise that things have changed.
As for what to call the class with main method, it is up to you. There is some good advice here. https://softwareengineering.stackexchange.com/questions/208062/naming-conventions-for-java-classes-that-have-a-static-main-method
You could also try a complete reset of the project. Create a whole new project, with the packages named (and cased) the way you want. Then, move the code files from your old project into the folders for your new project. IDEA should be able to see the files you put in there and parse them correctly.
Just clean the contents in /target (or "mvn clean"), and Intellij can find your new package correctly.
Having strange problem for couple of days.
I have written 2 main files, so to test based on need.
I have been facing following strange problems,
The main fail stops executing after some statement. doesnt hang! after cleaning the build, and compiling again it got executing!
I updated few System.out.println statements, but i am cant see new statements.
I excluded the unwanted main files and tried. even commented the whole unwanted main files and tried.
I even tried changing the main file name that i am using.
I observe the eclipse is not compiling the main file i wanted or it is taking old class file some where residing?
I cant see the unwanted class anywhere in the workspace!!
anyone experienced similar problem?
Please try right-mouse click on the class in "Package Explorer", then
form the menu choose "Run As" -> "Java Application".
This will run (and compile if needed) the selected source code.
I copied a main file from other project, and that package got retained in that file. when i modify the code in copied main file, forgot to modify a constructor name which was pointing to earlier package. I missed to trace import statements and it was not expanded. when i try to copy the file to post in stackflow, i found earlier package was included and found that was the culprit!!
So I'm making a java application in Neatbeans 7.4, been working at it for a while, everything was fine, running the project worked fine, but now when I hit run project, I get the error
Error: Could not find or load main class phleveledit.MainWindow
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)
I can't think of what I did right before this started happening, so I don't know what I should change.. The code doesn't appear to have any errors. Here's a screenshot of the IDE+project folder
Image (http://puu.sh/5ldYB) :
Any ideas?
Edit: Unfortunately I happened to fix this problem by removing some code, which probably had some errors Netbeans couldn't detect, but I don't know what was exactly wrong so can't vote on a correct answer.
Right click on your Project in the project explorer
Click on properties
Click on Run
Make sure your Main Class is the one you want to be the entry point. (Make sure to use the fully qualified name i.e. mypackage.MyClass)
Click OK.
Clean an build your project
Run Project :)
If you just want to run the file, right click on the class from the package explorer, and click Run File, or (Alt + R, F), or (Shift + F6)
Just close the Netbeans. Go to C:\Users\YOUR_PC_NAME\AppData\Local\Netbeans and delete the Cache folder. The open the Netbeans again and run the project.
It works like magic for me.
(AppData folder might be hidden probably, if so, you need to make it appear in Folder Options).
You can :
RightClick on project node and go to Set configuration
Select the main class for your application.
Then clean and build.
Even if the above steps don't work for you then then delete the Netbeans cache by deleting the (index) folder
User\.netbeans\SOME_NUMBER_reflecting_your_version\var\cache\index\
Sometimes due to out of memory space error, NetBeans does not load or find main class.
If you have tried setting the properties and still it is not working then try
Select the project from the project explorer
Click on Run in the Menu Bar
Click on Compile
It worked for me.
This condition happens to me every 6-months or so. I think it happens when closing NetBeans under very low memory conditions. I discovered that it could be easily corrected by (1) Rename your project, including its folder name using right-click on project explorer's project name---I put a simple suffix on the original name ("_damaged"). (2) Try BUILD. If that is successful, which it is for me, give three cheers. (3) Repeat step (1) to restore the original project name. BUILD and RUN should start without trouble.
I guess that the 'rename the project and folder' process causes a special rediscovery of the applications main location.
Try to rename the package name and the class/jframe names... The clean and build the application.
Right Click on the package name
Go to Refactor
Select Rename
Give it a meaningful name, preferably all in small letters
Click on Refactor
Do the same for the class/jframe names.
Last Select Run from Menu
7.Select Clean and build main project
That should do it!!! All best
I had the same issue once. The problem was not in the code. The cause was... renaming the project folder to some other non supporting name. My project name was "MobStick" and I renamed it to "MobStick - May 26, 2014 04:00PM". Renaming it back to normal solved my problem.
I have run into this error a couple of times as well and for me the above solutions did not work. What does seem to work is going to the Project Properties, and under Compiling toggling Compile on Save.
Using NetBeans 8.1, I got the dread
Error: Could not find or load main class
from carelessly leaving an empty line in the Project Properties > Run > VM Options field. Until you click in the field, you may not see the caret flashing out of place. Remove the empty line to restore equanimity.
I just ran into this problem. I was running my source from the command line and kept getting the same error. It turns out that I needed to remove the package name from my source code and then the command line compiler was happy.
The solutions above didn't work for me so maybe this will work for someone else with a similar problem.
I had the same problem, I had the package and class named the same. I renamed the class, then clean and build. Then I set the main class in the "run" under the properties of the project. I works now.
I found the following steps useful:
Right-click on the project in the left toolbar.
Hover over the 'Set Configuration' item.
Click on 'Customize...'
Click on 'Browse...' by the 'Main Class:' item.
Select the correct class.
Click 'Select Main Class'.
Click 'OK'.
My problem was that, apparently, my package name was being listed twice. Selecting the class using the dialog changed 'aclass.MainClass' to just 'MainClass'.
Hope this helps,
-HewwoCraziness
Edit: This is expanding on Mary Martinez's answer.
You can solve it in these steps
Right-click on the project in the left toolbar.
Click on properties.
Click on Run
Click the browse button on the right side.(select your main class)
Click ok
Possible Fixes:
Fix 1
Go to project properties (right click on the folder of your project in netbeans)
On left tab where it shows the categories, click on the "Run" selection
Then click on Browse to find the Main class you use on your project
Fix 2
Go to C:\Users\name\AppData\Local\Netbeans
delete the Cache folder.
Rebuild and Run
Fix 3
Download most recent version of Netbeans
Fix 4
Download most recent version of JDK and configure Netbeans to use that
I had the same problem for 3,4 days. On my PC my Jar file snapshot would give me this error while on my laptop it would work fine, I tried all the tricks shown above and on other forums like deleting cache, selecting main project file, etc, but somehow I was sure the reason it cannot find the main class when I would execute the JAR file was may be due to classpath issue in maven configuration, and I was right and I fixed it using following steps:
Right-click on the project, and go to the properties
Inside the properties go to Actions
On the right side in Actions select "Run Project" and you will see properties below
Inside "Set Properties" make sure exec.args=classpath %classpath "package_name"
In my case, the package name was accompanied by the main class. So my main class was Login while the package name was com.mycompany.islamic_center_app1, When I checked the entry was
com.mycompany.islamic_center_app1.Login
All I did was remove ".Login" from com.mycompany.islamic_center_app1 and it was fixed, no more errors.
close netbeans.
open netbeans again.
choose new project>>java application.
click next.
deselect create main class.
now make the application
clean build run
For more reference watch this video
try this it work out for me perfectly
go to project and right click on your java file at the right corner,
go to properties,
go to run,
go to browse, and then
select Main class.
now you can run your program again.
I had the same problem and I moved the project to a location where the path had no none-english letter and that fixed the problem
if you are on window os, then try to start NetBeans via administrative mode. right click on NetBeans icon and "Run as Administrative".
If none of the above works (Setting Main class, Clean and Build, deleting the cache) and you have a Maven project, try:
mvn clean install
on the command line.
Had the same problem here. Usually Clean and Build solves much of the problem. It happened to be caused by a wrongly installed plugin.
I faced the similar issue with Netbeans 10 and JDK 1.8.
I was not able to choose the right class to launch the project
When I compile or run the project, it shows me the Class name as "initializing view, please wait ...", I could not select the class name.
The issue was resolved with the NetBeans11.3, I am able to choose the correct Class file without any other changes, and the project is launched without any issues.
I had the same issue but none of this thread's solutions worked for me. Finally, it was OneDrive that caused the issue (for once more). So, I simply moved the NetBeansProjects folder from Documents which is synced with OneDrive, to C:\Users\yourName\AppData\Local\NetBeans (selected this path as there is already a NetBeans folder) and that was it, case closed.
If you also have NetBeansProjects to a OneDrive syncing folder it is worth trying this solution, just be sure that the path you will select is not synced with OneDrive. Also, remember to close Netbeans before making the folder change and after you move the folder to the new path you need just to open Netbeans again, go to file menu/open project and select your project from the new path.