IntelliJ IDEA: ClassNotFoundException if run Debug, execution/run does work - java

I have a Java Maven Project started in Eclipse, worked on it a few days, then imported it in IntelliJ IDEA, again working on it a few days.
The normal Run/Execution in IDEA and via shell does work, but not the Debug.
When I click the Bug Icon for Debug, it opens up URLClassLoader.java file and points on the Line "throw new ClassNotFoundException(name)" and pauses the Debug, if I click Resume Debug, it shows several Classes that do not belong to my project. I can click the Resume Button endless, it shows the same classes, also ClassNotFoundException over and over again in a continuously loop and does not debug my source.
If I click Build -> Rebuild Project it says at the Debug icon
"Hot Swap failed
myClassname: schema change not implemented;
myClassname: Operation not supported by VM"
In the Debug window under Variables it says: "Frame is not available"
The Debug of this project in IntelliJ IDEA did work previously, whats wrong now?

Looks like you have an exception breakpoint on ClassNotFoundException. Please try to open Run | View Breakpoints... and uncheck the breakpoint under "Java Exception Breakpoints".

in my situation, just neglect the evaluate language drop down.

This is really helpful. Go to your breakpoints in debug mode and make sure to deselect all the breakpoints first and then select only the ones in your class.

Related

Make Eclipse forget “remember my decision” for Terminate/relaunch application

While debugging java application in eclipse, the dialog for opting Relaunch/terminate appeared. I have selected the option to terminate the application, but now unable to change this option.
In eclipse settings, section Java > Debug, try checking the box 'Show error when hot code replace fails'.

Eclipse → AndroidStudio: Where can I see my errors?

I'm trying to migrate from Eclipse to Android Studio. There are a few things that bug me, but one stands out:
Q1: Is there no way to do automatic builds and have a list of problems displayed immediately like in Eclipse?
I know, there are many refactoring tools, but my often-used practise is to just insert a character into the name of a method and variable and check problems-view to see where it's being used.
Q2: How can replace or replicate this workflow in Android Studio?
One thing you can do is deactivate the external build. To do so click on "compiler settings icon" in the "Messages Make" panel that appears when you have an error. You can also open the compiler settings by going to File -> Settings -> Compiler. (Thanx to #maxgalbu for this tip).
enter image description here
Uncheck "Use External build"
enter image description here
And you will see the errors in the console
EDIT: After returning to "internal build" again you may get some errors, you can solve them this way: Android Studio: disabling "External build" to display error output create duplicate class errors

Netbeans - Error: Could not find or load main class

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.

Eclipse + breakpoints = nothing happens

I'm trying to use Breakpoints in Eclipse, but when I set them - nothing happens.
Really.
For example in MVS when the program reachs breakpoint it stopps and I can see variables.
How to use breakpoints in Eclipse in the same way?
you need to be debugging the program, click the little bug next to the run button instead of said run button
First select Debug perspective as:
Then set Breakpoints at places you want:
After that create a Debug configuration via Debug As->Debug Configurations... and then Debug as Android Application as shown below:
Then in Debug perspective you can trace/watch value of your desired variable by pressing F8:
That's it, you can also evaluate expressions through Expressions view. If it is not enabled select it from:
Window->Show View->Other->Debug->Expressions.

Eclipse stepping into class in android

I have a simple android project that I am trying to debug inside of Eclipse. When I run it in debug mode and use the "Step Over" button, it frequently seems to want to go into Android code (I don't want it to do this, just as a C debugger will not go into libc). I get a screen that comes up which looks similar to:
Class File Editor
Source not found:
The JAR file blahblah/android.jar has no source attachment.
You can attach the source by clicking attach source
I don't want it to go into Android or Dalvik code at all
(even if I could install source code) I am only interested in my own personal code.
not sure if it works for Android, but for Java SE you can set Step Filtering in the preferences to avoid stepping into some package/class:
Window -> Preferences -> Java -> Debug -> Step Filtering
Mark "Use Step Filters", add the packages and classes to ignore, mark "Step through filters".
Eventually you need to turn off the "Suspend execution on uncaught exceptions" to avoid the debugger stopping in case of an exception:
Window -> Preferences -> Java -> Debug
Depending on how you "step" you may be run through some platform/SDK code while moving between Activities even if your code seems to be running clean. To work around this I set a breakpoint somewhere within the next Activity and step through the current Activity and then once I hit the end of the code I hit resume and it breaks in my next Activity skipping any code that is not mine. Not the most elegant, but it works for me.
In Debug you will always be run through the exception handling platform..
In Eclipse:
F5 = go into; F6 = jump over; F7 = go upwards: F8 = go to next
breackpoint or exit
I always use it like this and never had a problem. :)

Categories