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CheckStyle Java Installation | MIT Software Construction

I am following the eclipse set up from MIT's software construction course1. The installation yields an error and I am not sure how to fix this (pictured below)2. The URL yielding an error returns a 404 error, so I don't know if their site is down or an issue with the package I'm using from MIT. Any advice is appreciated!
Error Message From Eclipse

It seems the update site recently moved to a new location.
If you don't want to contact the course staff directly, you could raise an issue against the relevant GitHub project, suggesting they update the setup file.
In the short term, you should be able to download the file to disk, change the URL (look for a line like <repository url="https://checkstyle.github.io/eclipse-cs/update"/> and change the URL to https://checkstyle.org/eclipse-cs-update-site/) and use the "Browse File System" button in the Eclipse installer instead of pasting the remote URL.

Cannot run Apache Netbeans 11 using JDK 11

No matter what I do, I can't get Netbeans 11 to work with JDK 11. Can you help me out?
Please note that this issue does NOT occur with JDK 8.
Downloaded and installed JDK 11 to C:\Program Files\Java\jdk-11.0.4
Downloaded and unzipped Netbeans 11 to C:\Program Files\netbeans
The etc/netbeans.conf file has been edited to set JDK home:
netbeans_jdkhome="C:\Program Files\Java\jdk-11.0.4"
When trying to run bin/netbeans64.exe:
First time: The loading window appears, loads for a bit, and then the
whole program disappears.
Second time: Loading window does not appear. An empty Java application
appears.
If I go to Task Manager and manually end the Netbeans process, I can
get back to First time.
For the attachments listed below, please refer to the issue I created here:
https://issues.apache.org/jira/browse/NETBEANS-2865
Executing netbeans64.exe from PowerShell outputs error messages to the console. They can be found in consoleOutput.txt attachment.
The results from executing bin/netbeans64.exe --trace C:\netbeans.log can be found in netbeans.log attachment.
For reference, this is the tutorial I followed:
https://www.youtube.com/watch?v=cxh-hVty09g
Update & Solution
I FINALLY got it to work thanks to the answer provided by skomisa.
The issue was caused by Netbeans 11.0 importing settings from a previous version. There was a popup the first time I ran Netbeans 11.0 asking if I wanted to import my settings from a previous version. Refer to skomisa's answer for more details on why.
To solve it, I deleted ALL of the preference files for NetBeans 11 by deleting the entire folder in AppData.
C:\Users\Hunter\AppData\Roaming\NetBeans\11.0\
Skomisa's answer mentioned trying to create a new unzipped version of NetBeans 11 and not importing the settings. I had actually tried this previously, but never got the popup window asking if you want to import. I assume this is because the user preference files for this version of NetBeans have already been created and are still sitting in AppData.
This leaves you with two viable options:
Delete all of the user preference files for NetBeans 11.0.
Search through the entire folder for instances of \u0000 and remove them.
It seemed easier and more satisfactory to remove the entire folder and start from scratch. That way, all of my user preference files are using the newest practices accepted by the JDK and Netbeans and that, hopefully, there is no lingering legacy code that will randomly break the next time I update.
Thanks for everyone's help!

Your problem appears to be related to the IllegalArgumentException ("Key contains code point U+0000") in the console log output of your bug report. It looks like NetBeans is trying to import your preferences from an earlier release of Netbeans, and is is finding some invalid null character(s) in your preference file(s).
This has been bug reported before, but remains unresolved. See Bug 271652 - IllegalArgumentException: Key contains code point U+0000.
Your preference files are all XML files (with extension xml), and reside in various directories under C:\Users\user ID\AppData\Roaming\NetBeans\11.0\config.
In my case my only preference file for NetBeans 11 is named C:\Users\johndoe\AppData\Roaming\NetBeans\11.0\config\Editors\text\x-java\Preferences\org-netbeans-modules-editor-settings-CustomPreferences.xml but you may have more than one.
From the stack trace in your console log, the failing call is AbstractPreferences.getBoolean(), so the null is probably on a line containing Boolean in your preference file. However, as this somewhat related SO answer suggests, just blindly remove all nulls from all preference files. Nulls should never exist in any XML file anyway.
An alternative approach to solving your problem is to create a new unzipped version of NetBeans 11, but do not import your settings.
I suppose you could even locate the preference files in your existing (broken) NB 11 installation and delete them, though that seems like an unsatisfactory approach even if it works.
A few related points:
Seeing the NetBeans window appear briefly before it vanishes is often a symptom of having set netbeans_jdkhome to an invalid JDK path, but in your case the value looks fine.
JAVA_HOME is ignored by NetBeans, so that cannot be the cause of your problem. See the response to Bug 198950 - NetBeans should use the JAVA_HOME and JDK_HOME environment variables, if available, to determine which JDK to use for details on how NetBeans decides which JDK to use. Specifying the --jdkhome parameter when you start NetBeans will override everything else.
The IllegalArgumentException only arises with JDK versions >= 9 because of a JDK bug fix, but that's a good thing. See JDK-8075156 : (prefs) get*() and remove() should disallow the use of the null control character '\u0000' as key for details. You weren't getting the problem with NetBeans 8.x because you probably weren't ever importing any preference files, but even if you were the IllegalArgumentException would not have occurred due to the Java bug fixed by JDK-8075156.

"java.exe" exited with code 2 Xamarin.Android project

so I have my Xamarin.Android project which contains several libraries. When I try to build I receive an error which says "java.exe" exited with code 2.
After some hours of google research I found out that I could enable Multidex.
According to the blog entry of Jon Doublas I did the steps mentioned.
http://www.jon-douglas.com/2016/09/05/xamarin-android-multidex/
According to the blog entry Android API Level > 21 handles Multidex itself.
Well my experience is that it does not. I am building on API Level 25 and get the same error again and again with the same information.
The steps in the article do not help. It seems like Xamarin.Android does not support Multidex.
It seems like you have to handle Multidex by yourself but I haven't found any solution which is working. Dos anybody found a solution which works?
I am using Xamarin 4.6 and Visual studio 2017.

Found the answer after about 20 hours of searching in my project..
So here are the steps to resolve the problem "java.exe" exited with code 2
1) Change the MainDexClasses.bat as described in the link:
http://www.jon-douglas.com/2016/09/05/xamarin-android-multidex/
2) Make sure you have enabled Multidex Option in your Android Application! Have a look at the .csprj file if Multidex is set to true (in my case it wasn't even if I enabled Multidex)
3) Add the following part in your AndroidManifest file
<application android:name="android.support.multidex.MultiDexApplication"></application>
This will tell your Android project to actually use the Multidex-Option given.
After a clean and build I was able to run my application as it is.

After finding this question and #Daniel_97s answer I was able to solve this error only by adding multidex to the project without changing MainDexClasses.bat:
Check the option in Project Options:
Add MultiDexApplication to Android Manifest:
<application android:name="android.support.multidex.MultiDexApplication"></application>
Note I was getting this error code 2 on Visual Studio for Mac and on Windows the same app was building successfully. (why?)

The solution in my case was to disable the "Sign the .APK file using the following keystore details". Because the keystore location and/or password was incorrect, java.exe exited with code 2.

I only go to option > Build > Android Build and check Enable Multi-Dex it will resolve

My .csproj file had an entry for the KeyStore that was no longer valid, even thought right-clicking the project and inspecting the properties indicated that I had pointed it to the new location.
Within .csproj look for all instances of <AndroidSigningKeyStore> and update accordingly.

I've struggled with this issue for quite a long time. I found source of the error in signing - as I cloned project repo from company TFS, Android csproj file had entries for KeyStore settings and location. I didn't have the keystore and the location on my drive was invalid. Visual Studio is then unable to sign the app while deploying and instead of some sort of FileNotFoundException it gave me just java exited with code 2. So...
tl;dr: Go to android project properties, select package signing a uncheck "Sign the apk file..." (which changes csproj <AndroidKeyStore>true</AndroidKeyStore> to false) and voila, you can now run your solution.

Reassign the path of the keystore worked for me
==EDIT 01==
Double click on Android Project > Android Package Signing
On the Keystore path, don't know why but apparently the path was wrong, I re-select the .keystore file again from the same path, and the error "exited with code 2" went away and I was able to Archive for release

Disable sign the .APK file using the following keystore details as #Klemikaze

I had this error when switching from VS Mac to VS Windows.
Here the topic Switching From VS Mac To VS Windows got “java.exe” exited with code 2
The issue was comming from the Android.csproj and the Keystore Path.
It was set to my Mac Path even if I changed it on
VSWindows AndroidProject => Properties => Signin
So I removed this lines on Android.csproj (edited with third text editor):
<AndroidKeyStore>True</AndroidKeyStore>
<AndroidSigningKeyStore>YourMacPath/Alias.keystore</AndroidSigningKeyStore>
<AndroidSigningStorePass>Password</AndroidSigningStorePass>
<AndroidSigningKeyAlias>Alias</AndroidSigningKeyAlias>
<AndroidSigningKeyPass>AliasPassword</AndroidSigningKeyPass>
On debug & release Part.
Then you can edit them on VS Windows.
Hope I helped someone.
See ya

In my case this was link to the "Sign the .APK file using the following keystore details" option as Hein Andre Grønnestad mentioned.
The location was not correct.
I wanted to put a path that could work for everyone at work so I used $HOME/Library/... instead of /Users/Me/Library/...
The problem is $HOME doesn't mean anything special for java so the keystore file could not be found.
Solution: use relative path or absolute path without $HOME variable or ~

For me, it was a problem with my Keystore. Follow this link to enable diagnostics. This will give you a more detailed error message in the output window. If it says that your keystore failed to verify, you will have to fix your keystore. This solved the problem for me.

In my case solved the problem by signing the .APK whit the values signed into the keystore that we configured to create the APK file in Release mode.
I taked the Microsoft example in here
and here I put the same values
That way a solved my problem with
"java.exe" exited with code 2
But the real information problem was in output:
Failed to load signer "signer #1"
java.io.IOException: Invalid keystore format
At the moment I don't find the real solution to this problem but, this works.

Please Update your Visual Studio to Latest version, if you are still using an old version.
If you think there is no solution then go and enable the Multidex

In my case the one of keystore details was wrong, after saving-> cleaning -> building process it worked.

Try reset the keystore <AndroidSigningKeyStore> or change to false the key
>
<AndroidKeyStore>true</AndroidKeyStore>
Only to check. But remembering that it needs to be set to true.
After Clean and Rebuild the solution.

For me it turned out I had Eclipse Temurin JDK installed and that was being used. In VS Tools>Options>Xamarin I changed the path to Java Development Kit Location to from the Eclipse path to C:\Program Files\Microsoft\jdk-11.0.12.7-hotspot.
Maybe more importantly, I discovered Eclipse Temurin JDK was being used by running:
msbuild /bl /t:"Restore;SignAndroidPackage"
in my solution dir and then opening the resulting msbuild.binlog and clicking on the few errors and a path with Eclipse stood out. Your problem may be different but finding it this way may be the key to solving it.
EDIT: My settings don't stick after closing and reopening VS 2019. At this point I started using VS 2022 and don't have the issue.

Note: Multi-dex is enabled.
After 5 hours of looking or an answer, this is the conclusion I've found -
Enable diagnostic MSBuild output within Visual Studio, so you can see more details about your error:
Click Tools > Options...
In the left-hand tree view, select Projects and Solutions > Build and Run
In the right-hand panel, set the MSBuild build output verbosity dropdown to Diagnostic, Click OK
Clean and rebuild your package. Diagnostic output is visible within the Output panel.
If your error shows "java.io.IOException: Invalid keystore format", you are probably using an outdated Java sdk file, so do next:
Open Visual Studio and update the Java Development Kit Location to
point to the new JDK under Tools > Options > Xamarin > Android
Settings > Java Development Kit Location:
Be sure to restart Visual Studio.

My experience is...
I updated the following elements:
Xamarin.Android.Support.Design
Xamarin.Android.Support.v4
Xamarin.Android.Support.v7.AppCompat
Xamarin.Android.Support.v7.CardView
Xamarin.Android.Support.v7.MediaRouter
from 26.1.0.1 to 28.0.0.3
Then, after it started the issue with:
"java.exe" exited with code 2 Xamarin.Android project.
I just ticked the Enable Multi-Dex inside the Android project property. I am using VS 2017 in windows system.

ERROR: Does not contain source for Thread.class - Class File Editor

First time post, long time watcher. Can't wait for my classmates to read this (they use the site too)
I am using Eclipse Juno w/ Java SE 1.7
I am having an eclipse problem. It doesn't happen all the time, typically only during File IO. I'm using my debugger perspective in Eclipse to try and trouble shoot some problems (its really a simple program).
UPDATE: Apparently new users are not allowed to upload screen shots. If you could take the time to click on the link to witness my problem I would appreciate it.
Screen Shot Link (not java code):
imgur.com/5IxI3.png
As you can see I am getting an odd thread.class problem. I have even reinstalled java. Could it be something with my code as well then?
Thanks for anyone who offers input or helps in anyway. I do have about a week before this is do so I'm not just looking for free answers, just frustrated. Thanks!

If I understand your question correctly, you need to attach source because Thread is API class.
Download Java source (not binary exe file) from Oracle
Go to eclipse Yourproject --> Properties --> Java Build Path >
Libraries and expand JRE System Library --> jre version--> rt.jar.
Select Source attachment ---> Point to the down loaded source.
Read this tutorial for more info.

Incompatible magic value 1008813135

I am writing a Java applet and embedding it in a web page.
It used to run Mac and Windows in different browsers without problem.
I was using NetBeans on the Mac to build the .jar file the applet used.
For some reason or another I decided to load the project on the Windows' NetBeans - I started getting the following error on the Windows machine when accessing the web page from any browser:
java.lang.ClassFormatError: Incompatible magic value 1008813135 in class file
Fearing that it must have been my decision to open the project on Windows that caused this error - I tried to build from the Mac's NetBeans - but the error persisted.
I started a while new project on the Mac and imported the existing source code: still same problem.
I was doing some reading about this error and it seems that the magic number expected is 0xCAFEBABE in hex which is 3405691582 in decimal, not 1008813135. So it looks like the Mac version of Java doesn't produce this file header any more? Hoe can that be? I didn't do any updates or anything.

Yes, 0xCAFEBABE is the usual first 4 bytes of a Java file.
1008813135 is <!DO in Latin encoding, which is, in all probability, the start of <!DOCTYPE....
It is therefore likely the start of a 404 error, or some other error page.

I have not experienced this problem, but Googling this error yields several possible solutions:
forum.sun.com - Java Applet Development - Incompatible magic value 1008813135 in class file MyApplet
Thanks God the problem is solved.
Its the Java cache, so the solution go to Java Control Panel, "General" tab, and under "Temporary Internet Files" click "Settings", then click "Delete Files". Try using the applet again.
"Incompatible magic value 1008813135" Error?
The problem is now solved: I found out that the website host I was using didn't support .jar files at all. I mass-uploaded the files with my ftp program and didn't notice that it ignored the .jar files completely.
Errors on java initialization
Alright, so it was an apache configuration issue, removed this line from my httpd.conf file:
# DefaultType application/x-httpd-php
Fixed the issue.

If you are using Spring security or some sort of custom Servlet Filters, make sure, that the archive or codebase location is in "permitAll" access. This was to problem in my case

I was facing the same problem.The reason in my case was all dependency library that Applet uses was not signed and also applet not able to locate them.
So i Have added all the dependent library along with main applet in jsp file like below :
app.archive = '/esense/resources/lib/Applet.jar, /esense/resources/lib/jasypt-1.7.jar, /esense/resources/lib/mysql-connector-java-5.1.30.jar, /esense/resources/lib/runtime-api-1.0.jar';
I have also signed all the jar.
Hope this may work in your case.

The incompatible magic number is the first four bytes of a html file that has some error message in it, probably a message that the file isn't found.
I encountered this phenomenon when I didn't take case sensitivity into account in the codebase element of the applet tag. Things worked well on Windows, but the internet server I was using was running UNIX where filename case sensitivity is important. Making the case of all file and directory names in the code and codebase elements solved the problem.

I just clicked on maven->update project->include snapshot release in my spring boot and it worked.