Hope you're doing well. I'm creating this simple app where you write text into a TextField and it should write it within a new JSON File in the resources folder. I'm pretty sure that my code is perfectly fine upon checking it with my professors, however, upon importing the library as seen here:
And executing the following code when the button is pushed:
*I have the following imports at the top of my JFRame class (The IDE shows no errors under those lines) :
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
Gson gson = new GsonBuilder().create(); //<-- The error always comes from this line
I get the following error which I have no idea how to fix:
I have read that switching to a Maven project is an alternative but it's not recommended for my practical. Any solutions would be greatly appreciated. I must also further note that the jar file is located in my libs folder and it is there.
Many thanks!
Edit: They asked me how my program was executed and this is what goes into the compiler in vscode (I execute it in the Run -> Run without Debugging):
c:; cd 'c:\ContentBoxFinalPrac\ContentBox'; & 'c:\Users\ytobi\.vscode\extensions\vscjava.vscode-java-debug-0.32.1\scripts\launcher.bat' 'C:\Program Files\AdoptOpenJDK\jdk-15.0.2.7-hotspot\bin\java.exe' '--enable-preview' '-XX:+ShowCodeDetailsInExceptionMessages' '-Dfile.encoding=UTF-8' '#C:\Users\ytobi\AppData\Local\Temp\cp_chdymt7vzhi9in94pnpo6ha1h.argfile' 'ui.HomeScreen'
I download gson-2.8.6.jar from Maven Repository, after adding it to referenced libraries, the code works well:
Please check if your jar misses some parts. Open command palette and choose Java: Clean Java Language Server Workspace then redownload the jar and see if question goes away.
The issue has been fixed for those still searching. I had to install this SDK which I was missing from VSCode -> Here https://dotnet.microsoft.com/download/dotnet/thank-you/sdk-5.0.202-windows-x64-installer?journey=vs-code
and just create a new project in the left hand bottom panel. Then import everything as you should and demonstrated by Molly Wang.
I'm asking this question even though it has already been asked many times because I didn't find a solution after hours of searching.
I'm using Eclipse to learn Java. Last week everything worked properly. I could run whatever I wrote. Then today, I opened Eclipse, wrote some lines and when I tried to run it, I got an error:
Error: Could not find or load main class test.ArrayTest
Caused by: java.lang.ClassNotFoundException: test.ArrayTest
But that's not all : every project in my workspace is having the same issue. I can't run anything. At first I thought it was because I made a mistake at Eclipse start, so I closed it and re-opened it, but I was in the correct workspace.
I've tried to clean/rebuild it, doesn't work.
I've tried to mess with Properties > Java Build Path, doesn't work.
I've tried to create a new project with a simple 'Hello World', doesn't work.
package Hello;
public class Main
{
public static void main(String[] args)
{
System.out.println("Hello World");
}
}
What I have in package explorer.
Console display.
The thing that suprises me the most is that I don't think I've done anything that can mess with Eclipse between the moment it was working and now.
Does someone have another idea ?
I think I found the root of the problem !
The path to my workspace was containing a letter with an accent ('Bibliothèque' by default with Windows 7+ in french...), so I tried to create a new workspace outside of it, and it worked !
I'm not a 100% sure it was really it, but since it worked, it's worth sharing.
Probably you have disconected JDK in project.
Try open conextual menu on project (right mouse button)
properties/Java Build Path/Libraries
check is correct JDK or remove
then: [Add Library] / JRE System Library/ Alternate JRE/ [Installed JREs] / [Add] / Standard VM / [directory]
select path to your JDK (not JRE) and confirm, select checkbox your new jdk and [Apply and close]
on select list choose your new jdk and [Finish] and [Apply and Close]
should works. I have sometimes this problems. It's Eclipse
How do I get IntelliJ IDEA to offer suggestions to resolve an unresolved symbol like Visual Studio does like in the picture below?
I wanted to use Aspose Cells for Java in a console application, so I downloaded the relevant JAR file and added a reference to it like so:
File -> Project Structure -> Dependencies Tab -> + sign
I am not sure why I do not see the library reference in the External Libraries node of the treeview on the left side.
Anyway, just because I wasn't sure, I also added the JAR files I needed to a newly created folder which I named lib and added that lib folder as a library like so:
Now, when I type in some code, the intellisense reports that it cannot resolve the symbol Workbook.
So, I qualify the type Workbook with its full name like so:
com.aspose.cells.Workbook and that symbols is resolved. To resolve all the symbols, I add the import com.aspose.cells.* statement on the top and the symbols are all resolved.
I was wondering why, like Visual Studio offers a suggestion for you to add the namespace on the top, does IntelliJ IDEA 2017.2 not give me suggestions to add the relevant import statement so I don't have to type it myself or even know what the correct import statement is?
Does it have such a feature? How do I use that feature?
I think you need to move the red line(Error line).
Press alt+Enter, then choose import class or(Something like this);
I have a dynamic web project that I am working on to migrate a jsp/servlet app from JRun to Tomcat.
I am getting the error: com.ibm.ivj.eab.dab.DatastoreJDBC cannot be resolved to a type.
I have the *.class files sitting inside a com/ibm/ivj/eab/dab folder (exactly how I found them). I have tried creating a jar file and adding that to the build path via "Add External Jar", I have also tried adding an "External Class Folder" and pointing to the folder that contains the "com" directory in question.
Still, the error persists. What is strange is if I start typing the package name eclipse actually auto-completes the class for me! (pictured below). Any ideas would be greatly appreciated. Maybe the classes were compiled for a much older java version and that is causing trouble? Maybe there is something I need to do to ensure the classes end up in the WEB-INF/lib directory?
I
Also If you are using mavenised project then try to update your project by clicking Alt+F5.
Or right click on the application and go to maven /update project.
It builds all your components and resolves if any import error is there.
Right click your project name.
Click Properties.
Click Java Build Path.
Click on Add Class Folder.
Then choose your class.
Alternatively, Add Jars should work although you claim that you attempted that.
Also, "have you tried turning it off and back on again"? (Restart Eclipse).
To solve the error "...cannot be resolved to a type.." do the followings:
Right click on the class and select "Build Path-->Exclude"
Again right click on the class and select "Build Path-->Include"
It works for me.
There are two ways to solve the issue "cannot be resolved to a type
":
For non maven project, add jars manually in a folder and add it in java build path. This would solve the compilation errors.
For maven project, right click on the project and go to maven -> update project. Select all the projects where you are getting compilation errors and also check "Force update of snapshots/releases". This will update the project and fix the compilation errors.
Project -> Clean
can at least sometimes be sufficient to resolve the matter.
For maven users:
Right click on the project
Maven
Update Project
Easy Solution:
Go to
Project property -> java builder path -> maven -> find c3p0-0.9.5.2.jar
and see the location where the file is stored in the local repository and go to this location and delete the repository manually.
Right click Project > Properties
Java Build Path > Add Class Folder
Select the bin folder
Click ok
Switch Order and Export tab
Select the newly added bin path move UP
Click Apply button
Solved the problem by dropping the jar into WEB_INF/lib.
copying the jar files will resolve. If by any chance you are copying the code from any tutorials, make sure the class names are spelled in correct case...for example i copied a code from one of the tutorials which had solr in S cap. Eclipse was continiously throwing the error and i also did a bit of googling ...everything was ok and it took 30 mins for me to realise the cap small issue. Am sure this will help someone
For many new users don't forget to add an asterisk (*) after your import statements if you wanna use all the classes in a package....for example
import java.io.*;
public class Learning
{
public static void main(String[] args)
{
BufferedInputStream sd = new BufferedInputStream(System.in);
// no error
}
}
================================================================
import java.io;
public class Learning
{
public static void main(String[] args)
{
BufferedInputStream sd = new BufferedInputStream(System.in);
// BufferedInputStream cannot be resolved to a type error
}
}
Solution :
1.Project -> Build Path -> Configure Build Path
2.Select Java Build path on the left menu, and select "Source"
3.Under Project select Include(All) and click OK
Cause :
The issue might because u might have deleted the CLASS files or dependencies on the project
Project -> Build Path -> Configure Build Path
Select Java Build path on the left menu, and select "Source"
click on Excluded and then Include(All) and then click OK
Cause : The issue might because u might have deleted the CLASS files
or dependencies on the project
For maven users:
Right click on the project
Maven
Update Project
First you need to update the pom.xml by adding below
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
1] Right click your project name.
2] Click Properties.
3] Click Java Build Path.
4] Check on 'Maven Dependencies' in Order and Export tabl.
In my case, previously it was not enabled. So when I enabled it my #GetMapping annotation works fine..
Also, there is the solution for IvyDE users. Right click on project -> Ivy -> resolve
It's necessary to set ivy.mirror property in build.properties
I just closed all the files and reopened them, and voila!!! Hope this helps someone in the future ;)
Download servlet-api.jar file and paste it in WEB-INF folder it will work
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.