I've been using Eclipse for a while and I'm having trouble understanding what's going on with my first project in IntelliJ. I've read the documentation, and searched other questions, but I still can't seem to grasp it. I think there is something wrong with my project structure. This is what my structure currently looks like;
I'm trying to run the JavaForLoop class, but whenever I do, compilation fails because I have errors in the StringMethods class of the strings package. My question is why would that prevent compilation if the two classes are in separate packages? Neither class uses the other, and they both have the appropriate package declaration statements. With a similar structure in Eclipse, this would work. Should I be using a different project structure?
By default IDEA adds Build Configuration which is executed before launch and includes following steps (taken from here):
Compiling source code in the source path of a module and placing results to the output path.
Compiling source code in the test path of a module and placing results to the test output path.
Creating copies of the resource files in the output path.
Reporting problems in the Messages tool window.
check if it's your case in Edit Configuration screen and if so, remove it.
To use a class from a different package you must declare a import statement to the class.
In your JavaForLoop.java add the import before the class statement (and after package declaration where its the case)
//package ...
import strings.StringMethods;
//public class JavaForLoop { and the rest of the code
Intellij uses regular javac, which will fail to compile if you have errors anywhere in the code.
Eclipse has it's own compiler, that allows to compile and even run code that has compilation errors, causing a runtime exception if any part of the code that has errors is run. This allows you to run parts of the code that work even if other pieces of code are failing.
The simple solution is to resolve your compilation errors. You can also use the eclipse compiler with Intellij, but I've never done this so I can't comment on how well it works.
I'm building an optimization program using Optaplanner 6.2.0.CR4, and I'm running into reflection issues with the ReflectionPropertyAcessor class, line 63: return readMethod.invoke(bean) and the other invoke methods in this class. Debugging the code, I'm usually able to "Step-into" the code into whatever of my classes it's calling, but Eclipse throws an error every time it reaches the end of whatever method is being called. This results in Method.invoke(Object, Object) line not available, DelegatingMethodAccesorImpl.invoke(Object, Object[]) line not available, GeneratedMethodAccessor5.invoke(Object, Object[]) line not available and then a screen asking me to change the attached source.
I'm running JRE 1.8, and I have the source code for Optaplanner imported into Eclipse as its own Maven project, with my code as its own separate Java project for now. I'm pretty new to using Maven and build tools in general. Could this error be a result of bad dependencies, classpath, etc? Is there a better way to set up my project? I'm in the process of moving my code into a Maven project also.
What stacktrace are you getting in a normal run?
The call readMethod.invoke(bean) can fail if bean isn't an instance of the class for which the readMethod applies. If that's the case, I'd be interested in seeing the code, because optaplanner might be able to detect that fail-fast with a helpful error message.
Debugging won't work because Method.invoke is probably a native implementation (C instead of Java) in the JDK.
I am working on moving code from R2007a to R2013a. I am getting a java.lang.NoClassDefFoundError during my run in R2013a which does not appear in R2007a. It occurs when I call.
feval('get',fname,jevent);
Where fname is a product.ProxyField object for an Object Filter and jevent is a product.format.java.internal.JavaEvent.
The class is in a jar file on the path and is being accessed by another class in the same jar file. The stack trace does not leave the realm of the product if that helps.
I do not have access to the original code for the jar file. I do have access to code derived from that original code and both classes are in the same package. I'm guessing this has something to do with differences in the java version but I'm not sure what to do since I don't have the original code to recompile.
Unfortunately I can't provide actual source or full detail but a google search only yielded results for MATLAB startup issues. Any thoughts?
Seems like the difference between R2007a and R2013a is that the first uses 1.5 jre and second uses 1.6 jre. It would be easier to help you if you provided the stack trace showing the exception. Sometimes classes get moved around in between jvm versions, so having the actual missing classes would help in determining if the missing class is a class that was just moved around to a different package. You could take the missing class, google it adding the same exception message as you put above and seeing who else ran into similar issues.
I'm a beginner in Java and am trying to run my code using IntelliJ that I just installed as my IDE with JDK 1.7. The following piece of code keeps does not even compile and keeps giving me the error:
Error: Could not find or load main class libTest
Code
import java.lang.Integer;
import java.lang.String;
import java.lang.System;
import java.util.*;
class book {
private String name = "trial";
private int bookCode=1;
private int issued=0;
public void Issue(){
if(issued==0) {
issued=1;
System.out.println("You have succesfully issued the book");
}
else {
System.out.println("The book is already issued. Please contact the librarian for further details");
}
}
public int checkCode() {
return bookCode;
}
String readName() {
return name;
}
public void setName(String newName){
name=newName;
}
public void setBookCode(int newCode){
bookCode=newCode;
}
}
class library {
private ArrayList books=new ArrayList();
public void getList(){
for(int bk:books){
String bName=books(bk).readName();
System.out.println((bk+1)+") "+bName);
}
}
}
public class libTest{
public static void main(String[] args){
library newLib= new library();
System.out.println("code working");
}
}
Is there any change that i have to make in the compiler settings?? Or is it the code.
This might help:
1) "Build" menu -> "Rebuild Project".
Sometimes Intellij doesn't rewrite the classes because they already exist, this way you ask Intellij to rewrite everything.
2) "Run" menu -> "Edit configuration" -> delete the profile -> add back the profile ("Application" if it's a Java application), choose your main class from the "Main Class" dropdown menu.
3)"Build" menu -> "Rebuild Project".
If none of the above answers worked for you, just close your IntelliJ IDE and remove the IntelliJ IDE file and folder from the root of your project:
rm -rf .idea *.iml
Then open the project with IntelliJ. It must work now.
For me the solution was to fix the output directory under project settings. Before I was using just "target" for the Project compiler output. Instead I updated it to have a full path e.g. D:\dev\sigplusjava2_68\target
I had this problem and I tried everything under the sun that I could think of and on this site.
None of my Java classes were being picked up after I pulled from a remote branch. All the classes had red Js by their names in the Project Hierarchy, not blue Cs.
In the end, I tried to follow this tutorial and a few steps in tried something not described and fixed the issue:
https://www.jetbrains.com/help/idea/creating-and-managing-modules.html
Here's what I did:
Goto File | Project Structure, or press Crtl+Shift+Alt+S
Select Modules under the Project Settings section.
In the Sources tab click Sources on the 'Mark as:' line.
Click the Apply button.
For some reason, all my classes then had blue C's.
Someone with a better understanding of how IntelliJ and/or IDE's might be able to explain the phenomenon, but all I know is now it can see all the classes and more importantly the main one, and run.
Invalidate cache and restart your IntelliJ, it worked for me.
Explicitly creating an out folder and then setting the output path to C:\Users\USERNAME\IdeaProjects\PROJECTNAME\out
seemed to work for me when just out, and expecting IntelliJ to make the folder wouldn't.
Also try having IntelliJ make you a new run configuration:
Find the previous one by clicking
then remove it
and hit okay.
Now, (IMPORTANT STEP) open the class containing your main method. This is probably easiest done by clicking on the class name in the left-hand side Project Pane.
Give 'er a Alt + Shift + F10 and you should get a
Now hit Enter!!
Tadah??
(Did it work?)
File > Project Structure > Modules > Mark "src" folder as sources.
This should fix the problem. Also check latest language is selected so that you don't have to change code or do any config changes.
I know this was asked a while ago, but I was just stumbling over this issue and thought my findings might help others. As pointed out, the error message is basically a result of the out folder. That's because, when you're trying to run the program, it compiles the code first, and puts the compiled result to the out location, and then it tries to load the compiled code from the out location. If the compiled code is not in the location expected, you'll get the error.
The point I'm particularly wanting to share is that some times, the code is not compiled (built), even though your run configuration specifies "Build" in the "Before launch" section of the configuration panel.
When can this happen?
One situation that can cause this to happen is if you're using modules and you manually delete the module out directory. For example, if I have a module named "foo", there should be a directory named foo under out/production. If you manually delete it, the build system may not know that it needs to be rebuilt.
Even worse, if you select Build | Build module 'foo', it still may not rebuild the module. If that's the case, you should select a file in the module, for example 'bar.java' and then select Build | Recompile 'bar.java'. Now the out directory out/production/foo should be restored.
Since IntelliJ typically knows about any changes going on, this surprised me, and took me a little time to figure out, so I thought I'd share.
Check your class module : I have encountered this problem with intellij :
I have a maven multi-module project, the problem is that i runing a class which not exist the module within the configuration, so my problem is fixed by setting the right module ("edit configuration" -> "use class of module")
may this help you
I had to mark the "src" folder as "Sources". After restarting IntelliJ and rebuilding the project I could run the project without further issues (see screenshot).
Edit: You can access the "Project Structure" tab via File->Project Structure or by pressing Ctrl+Shift+Alt+S.
I ran into this problem when my Java class was under src/main/kotlin. After I moved it to src/main/java, the problem was gone.
I have faced such problems when the class is in the default folder, i.e. when the class does not declare a package.
So I guess using a package statement (eg. package org.me.mypackage;) on top of the class should fix it.
Open Modules Tab (Press Ctrl+Shift+Alt+S). I had two modules under one project. I've solved the problem after removing the second redundant module (see screenshot).
After creating your project in intelliJ, try running the following command:
mvn package
I have tried all the hacks suggested here - to no avail. At the end I have simply created a new Maven application and manually copied into it - one by one - the pom.xml and the java files and resources. It all works now. I am new to IntelliJ and totally unimpressed but how easy it is to get it into an unstable state.
Invalidating cache didn't work.
I edited the main class java file with a dummy change and ran it. It worked.
In my case the problem seemed to be related to upgrading IntelliJ. When I did this I overwrote the files from the old IntelliJ with the files from the new IntelliJ (2017 community to 2018 community). After that all of my projects were broken. I tried everything in this thread and none of them worked. I tried upgrading gradle to the latest version (4 to 4.8) and that didn't work. The only thing that worked for me was deleting the entire IntelliJ folder and reinstalling it. All of my projects worked after that.
I have tried almost everything suggested in the answers here, but nothing worked for me.
After an hour of just trying to run my application, I noticed that my project's path included non-ASCII characters (Arabic characters). After I moved my project to a path with no non-ASCII characters, it executed just fine.
Goto File-> Invalidate Caches and Restart .
Else delete rm -rf .idea *.iml
and restart InteliJ
You can run the maven command on the pom.xml file in your project directory:
mvn clean install
For me - i tried few of the options above, did not work. Then i just renamed my Application class and that probably forced intelliJ to build a fresh jar and error message started to change. Then i renamed it back and it worked.
Mark the directory as a source directory. Opened via Ctrl+Shift+Alt+S
modules.xml with wrong content, I don't know what's matter with my IDEA.
I inherited a bunch of .JAVA files from elsewhere and couldn't figure out how to get them to work in any IDE. Ultimately I had to go to the command line where the Main.JAVA file was and run javac Main.java. This created a bunch of .CLASS files. The IDE's were then able to figure out what to do.
I got this error when using Scala/SBT. IntelliJ could not find the main class, even though everything was set up correctly.
My solution: delete the <user>/.sbt/<version>/plugins/target folder, then restart IntelliJ.
You probably would have specified a wrong package and the package hierarchy would not be right. Look below
The ide would highlight the wrong path in that case.
I'm using IntelliJ with Spring and my main class is wrapped in a JAR.
I had to mark the 'Include dependencies with "Provided" scope' in the Run/Debug configuration dialog
We are at File/Project Structure..
Answer might be:
Folder indicated as "content root" needs a child folder where the code is.
Plus find the button that marks code as excluded and not.
Not to be confused with tickbox that states excluded without telling in what phase and what**
Is it compiler exclude or runtime exclude? You are doomed to test and lot.
So no that tickbox but icons and colors.
As an idea we need to crack how it was originally thought to work. They never got it to work in first place and started add things in premature codaculation style.
It has been so many years and you cannot expect any improvement.
But as cure we can hack out some way to get it right every time.
Another thing you can check here is the actual command that is being passed to the JVM and make sure it looks OK. Scroll to the top of your Run console, it should be the first line.
Spaces in your Run Configuration VM Options field will malform the app startup command and can result in this error message
-DsomeArgument="arg with space must be quoted"
I am working with Kotlin but am guessing the problem is the same. I would start a project, create a single file and add main to it and the IDE couldn't find the main.
I tried the things in this list and none worked. I finally mentioned my frustration on one of the IntelliJ pages and was contacted. Of course, it worked fine for IntelliJ. After a couple of days back and forth, I noticed that the highlight function wasn't working and mentioned that. It turned out something was wrong with the IDE settings. I still don't know specifically what was wrong but the fix in my case was to reset the IDE settings. File->Manage IDE Settings->Restore Default settings.
After this, the green triangle start icon became visible to the left of my main function and things continued to work normally for subsequent projects.
Thanks to Konstantin at JetBrain's support for his patience.