unable to watch expressions in eclipse - java

I have a Maven project which is cloned from Git. Project was successfully built and runs perfectly. However when i debug and try to evaluate functions/expressions, it gives me error saying --
expression must be compiled in the context of a Java Project's build path.
I read previous stack overflow answers and did the following (with no results)--
I added java nature to .project file and then added Java Project in source lookup. Still i get same error.
If i remove the Java project from source lookup and choose option --"Workspace folder" while adding Source lookup path, it gives me Null Pointer exception.
Can someone please tell me how to resolve this?

Try this !!!
Find the thread in your debug window that you are in the breakpoint for. Right click on it. Under relaunch should be an edit launch configuration selection. Select that.
Select Source tab. Add. Java Project. Select the java project that the code exists in.

Related

org.eclipse.core.runtime.CoreException: The class file is not on the classpath

from the beginning, while trying to deploy a war under Jetty, I have an error, and in order to understand from where the error is comming, I would like to put a breakpoint in a class (SimpleCDI) located in a dependency (a jar which is downloaded by MAVEN). I work under MAC and when I hit Command + Shift + T and look up "SimpleCDI" class, it points that the class is within org.jboss.weld package
Here is a printscreen of my research
And when I click on the "C SimpleCDI org.jboss.weld" line, it returns an error message
org.eclipse.core.runtime.CoreException: The class file is not on the classpath
at org.eclipse.jdt.internal.ui.javaeditor.ClassFileEditor.doSetInput(ClassFileEditor.java:694)
at org.eclipse.ui.texteditor.AbstractTextEditor$5.run(AbstractTextEditor.java:3154)
at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:437)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:353)
at org.eclipse.ui.internal.WorkbenchWindow$14.run(WorkbenchWindow.java:2195)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2191)
at org.eclipse.ui.texteditor.AbstractTextEditor.internalInit(AbstractTextEditor.java:3172)
I checked that I have the right dependency (weld-servlet-2.4.5.Final.jar) with
SimpleCDI" in it.
I noticed that the eclipse icon of my dependency "weld-servlet-2.4.5.Final.jar" is the following
It is a jar file without attached source. Actually, I can see this dependency in Eclipse in one of my module "Tourism-Services" (I have a Maven multi module project) in the "Referenced Librairies" folder with the icon mentioned above, but the Maven dependency that import this jar is located in another module "Tourism-Core" which is imported itself in "Tourism-Services" module. I notice in passing that I cannot see "weld-servlet-2.4.5.Final.jar" in "Referenced Librairies" folder of "Tourism-Core" module (why ?)
My main question is : why cannot I edit "SimpleCDI" class and put a breakpoint in order to debug upstream
I've also been using the CodeMix plugin, have you tried to remove the Open Type binding from the CodeMix preferences? Preferences -> Codemix -> Bindings. From there uncheck the "Open Types on COMMAND+SHIFT+T" and do apply and close. This will get you to use the regular Open Java Type from Eclipse.
Cheers
a plugin was causing the error. It is CodeMix plugin
I tried to uninstall it : help->Eclipse Marketplace->Installed
I obtain the following screen
I chose uninstall in the dropDown
But it doesn't work.
I have found a workaround : https://www.genuitec.com/forums/topic/uninstall-codemix/
But it is temporary. I tried to find CodeMix in Eclipse plugin folder (I work under MAC), but there is nothing. Do you see another way ?

Unable to install breakpoint due to missing line number attribute [duplicate]

This question already has answers here:
Eclipse - Unable to install breakpoint due to missing line number attributes
(42 answers)
Closed 5 years ago.
When i put breakpoint it show given error:
Unable to install breakpoint due to missing line number attribute
I tried most of the option found on stackoverflow still same issue.
Now same error shows still debugging works fine. Why this error come?
If the source code of the class is in a Java project and compiled by Eclipse, do the following:
Right-click on the project that contains the code and choose Properties...
In Java Compiler check Add line number attributes to generated class files (used by the debugger)
This mostly happens when the project is not built properly (can be due to many issues such as project build properties have not been set properly, build runtime issues, file paths and location reference issues of the source files to the project, etc..). Not only in Eclipse, but in most IDEs, this happens where the line number mapping is not synced with the source code.
I suggest to first check on the build properties and env setup to (clean and) build the project properly, and then try out and see.
Cheers

Why is Visual Studio trying to use the wrong JDK version?

I am trying to build WeatherApp, which comes from this tutorial, but I am seeing this error:
The specified task executable location "C:\Program Files (x86)\Java\jdk1.7.0_55\bin\javac.exe" is invalid.
and this warning (not sure if they are related):
Found conflicts between different versions of the same dependent assembly. In Visual Studio, double-click this warning (or select it and press Enter) to fix the conflicts; otherwise, add the following binding redirects to the "runtime" node in the application configuration file: <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"><dependentAssembly><assemblyIdentity name="System.Runtime" culture="neutral" publicKeyToken="b03f5f7f11d50a3a" /><bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" /></dependentAssembly></assemblyBinding>
I can doube-click the warning to make it go away, but the error remains. I am not sure why the project is trying to use that version of the jdk, as I have changed my xamarin optioins to point at Program Files instead:
Why is Visual Studio trying to use that versioin of the JDK?
Sometimes there's a sdk.caches file that will hold an old reference. Please try to delete both your obj/bin folders and see if that resolves the issue. If it doesn't, turn up your Build Output verbosity and attach a Build Output Log to your post:
https://forums.xamarin.com/discussion/27515/how-to-obtain-diagnostic-build-logs (XS)
http://blogs.msdn.com/b/msbuild/archive/2005/09/29/475157.aspx (VS)

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 Throws Weird ClassNotFoundException

Apparently, Eclipse can't find a class from within said class. Here is my error (for some reason, Stack Overflow doesn't like the formatting on here): http://paste.ubuntu.com/686811/
Here is my main method: http://paste.ubuntu.com/686812/
It was fine for a long time, but all of a sudden, it broke.
In Eclipse determine if the EscapeComponent is in your build path. An easy way to do this is by going to the "Navigate" menu and selecting "Open Type" and entering "EscapeComponent".
If Eclipse doesn't find any class by that name there's your problem.
Maybe you have the EscapeComponent lib in your build path you don't export it in runtime.
Go to project properties, "Java Build Path" option, "Order and Export" tab and make sure that the lib that holds EscapeComponent is selected.
Otherwise it won't be available in runtime and so NoClassFoundException happens.

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