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Why is Intellij Idea freezing during indexing?

I'm on Manjaro linux using Intellij Idea community 4:2022.1.3-1 and jdk 17 for this project, maven is also present
Intellij always hangs after it starts indexing the jdk, it's responsive for a period of time but if I type anything or open a new menu after it's begun indexing the jdk it will immediately freeze and I have to kill the process.
This behavior started after I began attempting to use the luaj-jse-3.0.2 library. I got it to successfully start by removing this library once but have been unable to replicate this since.
I have tried -
Reinstalling intellij
Installing a different version
Removing the luaj library (only successful once)
Deleting the .idea folder
Running intellij in strace
Waiting for it to resolve
Several combinations of all of the above at once
I'm really at my wits' end on this, anyone know anything?
project github (this is up to date to the project): https://github.com/MorticiaGrey/CompSim

Apparently maven was having an issue with the jar I imported through intellij as a library. On a new project without maven but with the offending jar and code copied and pasted from the original project it worked fine, I also got it to work by deleting the old project and importing it again from github without building any of the maven stuff and deleting all the maven files
It may have been my fault for configuring something incorrectly somewhere, but I was using the normal method to add a library in intellij so if that's the case whoops I guess

Eclipse Oxygen - The project was not built since its build path is incomplete

I just installed Eclipse Oxygen and tried to open an existing project into the workbench but I get this error:
The project was not built since its build path is incomplete. Cannot
find the class file for java.lang.Object. Fix the build path then try
building this project
I tried right clicking on the project - went to Properties - Java Build Path - Libraries - Add Library - JRE System Library and selected Workbench default JRE (jre1.8.0_60).
I then cleaned and rebuilt the project but it then causes more errors to come up like:
ActionBar cannot be resolved to a type
Activity cannot be resolved to a variable
AdapterView cannot be resolved to a type
ArrayAdapter cannot be resolved to a type

Here is what made the error disappear for me:
Close eclipse, open up a terminal window and run:
$ mvn clean eclipse:clean eclipse:eclipse

Are you using Maven? If so,
Right-click on the project, Build Path and go to Configure Build Path
Click the libraries tab. If Maven dependencies are not in the list, you need to add it.
Close the dialog.
To add it:
Right-click on the project, Maven → Disable Maven Nature
Right-click on the project, Configure → Convert to Maven Project.
And then clean
Edit 1:
If that doesn't resolve the issue try right-clicking on your project and select properties. Select Java Build Path → Library tab. Look for a JVM. If it's not there, click to add Library and add the default JVM. If VM is there, click edit and select the default JVM. Hopefully, that works.
Edit 2:
You can also try going into the folder where you have all your projects and delete the .metadata for eclipse (be aware that you'll have to re-import all the projects afterwards! Also all the environment settings you've set would also have to be redone). After it was deleted just import the project again, and hopefully, it works.

In Eclipse, Right click Project -> Maven -> Update Project. It fixed errors in my project.

I'm also using Eclipse Oxygen, migrated from Mars. I faced the same error. I deleted .metadata, .recommenders folders and added projects from archive and issue is solved. I also use Android Studio but i like Eclipse much more.

At my system the Java Runtime JAR file jrt-fs.jar was not found because it was in the wrong directory. This file should be located in the "lib" subfolder. If you installed Java at "C:\Temp\java" the file should be here at C:\Temp\java\lib\jrt-fs.jar .
These are the steps to make jrt-fs.jar available to Eclipse:
Window / Preferences -> the "Preferences" Window opens
Select in the left menu: Java / Installed JREs
Press the [Add...] Button -> A window opens
Select "Standard VM" - The window "JRE Definition" opens.
Enter your path information:
JRE home = "C:\Temp\java"
JRE name = "MyJRE"
Select [Add External JARs...] to link the jrt-fs.jar
JRE system libaries: "C:\Temp\java\lib\jrt-fs.jar"
It worked for me with OpenJDK12 and Eclipse 2019-09 (4.13.0).
Eclipse reported me this error:
The project was not built since its build path is incomplete. Cannot find the class file for java.lang.Object. Fix the build path then try building this project

I had faced this problem. I added the C:\Users\Office 2\android-sdks\platforms\android-19\android.jar to the Java Build Path's Library. And the project started to run again.
The problem occurred due to my carelessness. Yesterday night I was updating the Android SDK, and at the same time I tried to run the project, while the SDK Manager was uncompressing the system image. The Project couldn't start and the error occurred.
I tried all the methods given by others. But nothing worked. It solved when I added the android.jar to the library.
I guessed it that android library is missing. not the Java, when I saw the errors only at the android methods and imports. But when I read the posts, I got confused and wasted some time trying wrong way.

I had faced the same issue and tried different solutions, I have reinstalled my JDK 11 and restarted the machine, after that the issue gets resolved.

I got this out of the blue in a workspace that was working properly before. This problem seems to indicate that the project configuration somehow got corrupted.
Restarting Eclipse didn't help, but in the same vein as the answers dealing with Maven, regenerating the Eclipse project config with:
./gradle eclipse
or
./gradlew eclipse
if you use the wrapper, solved this problem for me.

I have similar issue when importing Spring Boot, jdk 11 (using
inside docker) project to Eclipse 2019 (2021), in Ubuntu, instead when
importing to Inteelij IDEA Community or NetBeans IDEs they do
not produce the same set of after-import errors as in Eclipse.
The Spring Boot is multimodule maven projects and two child
modules give such 2 "problems" in appropriate problems tab:
The project was not built since its build path is incomplete.
Cannot find the class file for java.lang.Object. Fix the build
path then try building this project
Next 2 errors are produced in two classes of aforementioned
maven modules:
The type java.lang.Object cannot be resolved. It is
indirectly referenced from required .class files
Manipulation with adding JDK 11 to submodules buildpath
just leads to the thousands of problems. Also it is
got when I use Eclipse-File-Maven-Update.
Moreover when I try to edit most of existing classes or add new ones
I got red underline that tells
Implicit super constructor Object() is undefined for default
constructor. Must define an explicit constructor
. So almost no opportunity to use Eclipse
even at prebuild stage as docker-compose should run build and
run. Indeed I noted that such issue is produced just when project
also uses modules (module-info files introduced in java9).
When I import project on jdk 8 (even not installed on
system), or even on jdk11 without module-info files all
is fine in Eclipse after import.
Another difference is that of when I use problem old no module
project the Build Path is composed with jre environment 8 and
maven dependency items, but when using
"module-info" project the Build path contains -module path,
and -classpath. So I even do not know where to add jre 11,
indeed adding does not resolve issue, just make more errors.
So what is the resolution of the case??? What settings to do
in Eclipse?

Eclipse for Java shows Multiple Errors

This is my current configuration:
Eclipse IDE for Java Developers
Luna Service Release 2 (4.4.2)
Java Version 8 Update 45 Build 1.8.0_45-b15
After a time without using some Java Project folders, now Eclipse throws a lot of syntaxis errors over them:
The import javafx cannot be resolved
*** cannot be resolved to a type
The method join(String, List<String>) is undefined for the type String
The project folder never change from their location, they were error and warning free prior to left them abandoned.
I am not sure about a missing .metadata or .reccomenders or a Java version change -over no more than two months- for these projects.
What should i do to solve that?

Try cleaning your project by going to the following menu item:
Project > Clean...
If that doesn't work:
Try removing the jars from the build path and adding them again.
Double-check the jars being really on the build path (with no errors).
Make sure there is nothing in the "Problems" view.

Project in Eclipse break when I launch it today

This morning I just open Eclipse and find my project (which was working perfectly last time I worked on it and ran it) with tons of errors.
Error with package: "java.lang.Class cannot be resolved" same for java.lang.Object
I tried to add in library my JRE again so the error on package is fixed with this but now ALL other lines of my project (all my imports in each file, all my class , ...) contain an error so I don't understand 2 days ago my packages and imports were well imported into my project and everything goes well and no it's like all my project just break and now I don't find the solution to solve this ..
Please help
Hi all,
Finally I re-add a JDK and install all packages updated for eclipse and now I just have errors with my imports it seems eclipse doesn't find the imports I want I think it's because I start my project to the university and want to continue it at home on my own computer so do you know how should I add this imports and then eclipse can use them ? (on eclipse Juno 4.3)
Thanks for answers

Go to 'Configure Build Path' and add the required libraries

java.lang.Object cannot be resolved in Eclipse

When I installed the latest installment in Mac OSX - the Mountain Lion - I experienced some problems getting Eclipse to work I also lost most of my Android developer files (but I still have my projects). I suspect this is due to the choice of removing the /Developer and move the XCode and other Apple developer tools (I placed my Android tools here).
I have now installed the latest version of Eclipse and the problem still seems to be around. There are errors in all my projects and I get an error message prompting:
The type java.lang.Object cannot be resolved. It is indirectly referenced
from required .class files
I tried to check the Java class-path both in Eclipse and in my terminal and these seems to be OK. java and javac both run in my terminal and there is a valid path to the java source files in Eclipse (Under Preferences, Java, Installed JREs). That being said I'm not an expert in Eclipse so there may be that I have misunderstood how this problem ought to be solved. Anyone here with similar problems or who know the cure?

Make sure that you have a valid JRE or JDK defined in the Java Build Path of your project. Right-click on your project, select Properties... and then Java Build Path.

I had this problem moving a Maven project from Eclipse to RAD. I had a JSP file that worked in Tomcat and JBoss, but threw a NullPointerException in WebSphere on the form definition during the compile.
Anyway, after transforming the Maven project into an Ant project (mvn ant:ant), I imported the Ant project into RAD and got this error. The fix:
Open the Java Build Path, selecting the Libraries tab.
Find the JRE System Library and remove it.
Add the JRE System Library.
Goofy, but it works. It must reset some property in a file. I don't know if the problem is the older version of Eclipse or RAD.

After updating my Android SDK to make Appcelerator Titanium happy, I started getting "java.lang.Object cannot be resolved" for my Android projects in (non-Titanium) Eclipse.
I updated all dependencies in Eclipse, and the error healed after a restart of Eclipse.

I had that error almost every time I launched Eclipse for the first time; if I close and then re-open Eclipse, the error is gone.
I found this solution useful, though (I've copied here to protect the link, credit goes to the original author):
In Eclipse go to Windows -> Preferences -> Java -> Installed JREs.
Select the currently active JRE/JDK and press the Edit button.
Select the rt.jar and change its position in the list of JRE system libraries (e.g. press the Up button once).
Confirm all changes, clean and rebuild the workspace.
The next time you face the problem reposition the rt.jar again (or reset the order by pressing the Restore Default button).

please select your installed system jre version from java build path.

Try the following and problem will go away
Close the project and reopen it.
Clean the project (It will rebuild the buildpath hence reconfiguring with the JDK libraries)
OR
Delete and Re-import the project and if necessary do the above steps again.

This is an annoying Eclipse Bug which seems to bite now and then. See http://dev-answers.blogspot.de/2009/06/eclipse-build-errors-javalangobject.html for a possible solution, otherwise try the following;
Close the project and reopen it.
Clean the project (It will rebuild the buildpath hence reconfiguring with the JDK libraries)
OR
Delete and Re-import the project and if necessary do the above steps again.
The better cure is to try NetBeans instead of Eclipse

I got this error and what I had to do was remove the JRE from the Window/Preferences/Java/Installed JREs and re-add it. This somehow cleared up eclipse's cache and rebuilt the project successfully. To get rid of the error in the file-editor I also had to close it and open the file once again.

My problem was that I had in Eclipse: Window / Preferences... and then in the tree on the left Java / Installed JREs: C:\Program Files\Java\jre7
I changed to: c:\Program Files (x86)\Java\jre7
It solved my problem.

I had the same issue and none of the above solutions worked for me.
Then I realized than the library (libs) folder was missing in the project. Once i added the libs folder and the corresponding Jar file, the issue was resolved..

If your project specific (or if not applicable, workspace default) JDK/JRE is being referenced correctly and you've just begun to get this issue out of the blue: restart Eclipse.
Unfortunately, "restart Eclipse" is one of the standard troubleshooting steps when a project won't build. Eclipse even has a dedicated entry under the File menu.

I had to add the JDK under the build path. After adding the correct build path it worked.

I just had to restart eclipse, and the error went away. Strange.

I solved this by pointing my eclipse to the jre available in jdk.

This error caused by invalid sdk is pointing in your project.properties file of your project.
project.properties -> target=android-19 . change to version which is installed in your eclipse.The error will be gone.

I had the same issue after moving from JRE7 to JDK7. Finally I had to remove the JRE7 configuration from the Eclipse preferences and then add the following two lines to the eclipse.ini file.
-vm
C:\Program Files\Java\jdk1.7.0_55\bin\javaw.exe

I had this problem, and I understood that Eclipse has automatically imported a core reference, instead of the reference for the project I needed.
Deleted the import, and rearranged it, and everything worked fine.

Same problem facing Me
Project->properties->Android
And select the api level and also go in java build path and check some external jar file path if we already add in it.update the jar file path

On "The type java.lang.Object cannot be resolved. It is indirectly referenced
from required .class files":
I found my project had 2 meta-inf.java files in 2 different directories with the same 'module ' on line one (a copy/paste error).
Once this was corrected, I cleared the meta-inf.java file with the issue, rebuilding it line by line, guided by Eclipse, until I had a working module configuration.