I'm using Spring Tool Suite (rejiggered eclipse) and for some reason, occasionally when I start a server (servers view pane, right click, start), instead of using the runtime configuration I've edited (specifically, with new VM args, e.g. -Xmx1234g, -Dlog4j.doAThing=true etc), it will generate a new runtime configuration (so instead of Server-Name, it will run Server-Name(1), or if that already exists Server-Name(2)) with defaults and run that instead. It's more irritating than anything, but I'd like to find out what the cause might be and fix it instead of just tolerating it running wrong.
Rather than right clicking on the server and selecting Run, try clicking Run -> Run Configurations... from the menu bar at the top of the screen and then find and run the server from there. Alternatively there is a green run button on the tool bars with a small down arrow next to it. There should probably be a launch option for the server shown there.
I have the default config called
The following worked for me:
Created config called X copied VM args from , copied User Entries JARs on the Classpath tab. Launched the config to verify it is working
Removed config . Only have X left
Now launching server from the Servers view launches my config X
Perhaps Classpath tab User Entries are not matchi
every now and then I am launching JUnit tests from within Eclipse by using
Run As > JUnit Plug-in Test
By default Eclipse assumes you are running something which requires a workbench and chooses in the "Main" section of the launch configuration
LaunchConfig > Main > Program To Run > Run an application >
org.eclipse.ui.ide.workbench
I can understand why this is the default, but for me (and for all in our team) this is never ever the case. We always need to run our JUnit Plug-in Tests as
LaunchConfig > Main > Program To Run > Run an application >
[No Application] Headless Mode
How do I change this default behaviour?
I am currently using Eclipse 4.4.
It seems a custom LaunchConfiguration-Extension is a viable solution attempt.
What I did was to create a new, custom LaunchConfiguration-Extension which is 99.999% build on the JUnitLaunchConfiguration. I only had to add a custom
BlaBlaJUnitPluginTestLauncher extends launching.JUnitLaunchConfigurationDelegate
which overrides the
launch(ILaunchConfiguration, String, ILaunch, IProgressMonitor)
method to adjust the application parameters according to our needs.
BlaBlaJUnitPluginTestTabGroup extends org.eclipse.pde.ui.launcher.JUnitTabGroup
To be able to initialize the LaunchConfig dialog with the default parameter, I had to:
Add a custom BlaBlaPluginJUnitMainTab extends PluginJUnitMainTab
Create a custom JUnitProgramBlock implementation (BlaBlaJUnitProgramBlock)
Creating an instance of BlaBlaJUnitProgramBlock in the BlaBlaJUnitPluginTestTabGroup.BlaBlaPluginJUnitMainTab.createProgramBlock() method
Overriding setDefaults-method (not sure if its really neccessary) in BlaBlaJUnitProgramBlock
Overriding initializeForm-method in the BlaBlaJUnitProgramBlock and adjust parameter there too.
Leading to the following result:
This answer is a near miss:
Try this:
Manually create and configure one "good" launch configuration.
Next time you want to launch a test that doesn't yet have a good launch configuration:
Select the file and invoke Run As > Run Configurations ... (i.e., don't yet select JUnit Plug-in Test!)
In that dialog select a good launch configuration of the same kind, and ...
Then click New Launch Configuration (upper-left corner)
Now the newly created configuration should "inherit" the configured values from the the good configuration.
Truth is:
You can duplicate an existing launch configuration (leaving you to manually select the test to launch)
The Debug team once had plans to support launch configuration templates.
Edit 2018:
Since Eclipse Photon, the Java debugger supports launch configuration prototypes. I just filed Bug 536728 to request this also for test launches. Feel free to chime in (or contribute) on that bug.
if u r looking for only shortcut for convenience then eclipse remembers last execution. After using run as and saving ur run config, just use "Run as" button in toolbar.
besides this eclipse comes with flavour for testers, u can check that out.
Also since you are talking about unit testing see if you can make use of ant build or even better converting to maven based project. Maven has integrated support for testing.
There seems to be a simple and effective heuristic in place, which decides whether or not a JUnit Plug-in Test should be run headlessly or with an application:
Make sure that the plug-in containing your tests has no dependencies on anything org.eclipse.ui.
Without that dependency [No Application - Headless Mode] is selected by default for newly created launch configurations.
With that dependency the default is Run a product, with s.t. like org.eclipse.platform.ide preselected.
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.
I may have a corruption problem in Eclipse run configurations. This happened after I dragged (or copy-pasted, I don't remember) a Java class called MyClass from project1 to project2. Then I deleted project1. When I create a new run configuration the name given is MyClass (1). In other words, it thinks there is already a run configuration called MyClass, so the new one will have to have a number appended. (Edit: There is no existing MyClass run configuration so there is no apparent reason for the appended number. In fact, I deleted all of my run configurations.)
How can I easily clean up meta-data and be able to build again with minimal manual effort?
If there is a meta-data deletion recommendation that gets rid of more than just run configurations, that probably would still be a good solution, if it does not create a lot of manual work to get set up to work again.
Edit: The problem might be caused by the fact that there is a launch configuration named MyClass - project1 visible in the export dialogue. project1 no longer exists, but this remnant lives on, tying up the class name MyClass. I am not sure if there is a difference between a run configuration and a launch configuration.
AFAIK launch configurations are stored on:
${WORKSPACE}/.metadata/.plugins/org.eclipse.debug.core/.launches
Take a look to the existent configurations and remove those that are not interesting to you.
And restart Eclipse
Open Eclipse. Follow Run => Run Configurations. You will see options on the left hand side. Under the Java Applications option, you will see the list of runnable classes (the ones have a main method). These class nodes on that list are right clickable. By right clicking on your running configuration, you will see New, Duplicate and Delete options. You can delete your old running configuration via delete option. To create a new running configuration, right click on Java Applications option and click on New and then configure it.
You could try starting eclipse with the -clean command line option.
On windows the easiest way to do that is to copy your shortcut to eclipse and add the option to the arguments list, then start using the new shortcut.
I'm doing my 1st steps in Android/GoogleApp, and I'm trying to explore the Jumpnote example:
http://code.google.com/p/jumpnote/
I was able to import the Android and Appengine projects to eclipse, but encountered the following issue when trying to run the Jumpnote-web part (android runs well).
When running the web part there is an error Main type is not specified which AFAIK implied that this project is missing a main function.
Is that indeed the case for jumpnote example and I need to manually add it, or am I missing something else?
Go to run Configuration
select JumpNoteWeb run configuration
You see in the main tab your project name and below it says main class
In the main class, put "com.google.gwt.dev.DevMode"
it should now run
*When I had this problem I also need to make sure that I put the src.shared folder into my project and had to change my build order so the app engine sdk, gwt sdk, and jre would build first