Norm Radder

From Google:

// https://support.microsoft.com/en-us/help/240791/how-to-run-programs-automatically-when-a-user-logs-on

To configure Notepad to run when any user logs on to a specific computer:

Click the bottom-left Start button to open the Start Menu,
enter gpedit.msc in the empty box and tap gpedit in the results.

Edit the following group policy:
Computer Configuration\Administrative Templates\System\Run These Programs at User Logon <<<<< Didn't find this, found just Logon
Type the full path name of the program. In this example, type the following path name:
c:\%windir%\system32\notepad.exe

 The advantage of java.exe is that it spawns a new console window

I have a custum registry entry so from the RightClick menu I can chose with or without the console window.

why its not opening your code

I'm not sure what that means.

Most of the error messages you posted were from missing android classes which are in jar files that need to be loaded into Eclipse.

From Eclipise Help:

Version: 1.4.1.v20120912-144938-8R7xFOXFLWUl7PpNBh_HIGkb4
Build id: M20130204-1200

The adt bundle:
D:\AndroidDevelopment\adt-bundle-windows-x86_64-20140702\eclipse

The registry shows that the javaw.exe command is used to open a jar file.

"C:\Program Files\Java\jre-10.0.1\bin\javaw.exe" -jar "%1" %*

My shortcut in the Startup folder has:

Target: D:\JavaDevelopment\runtime\TrayToolToCB.jar
Start in: D:\JavaDevelopment\runtime

not the login startup

I don't logout/login and haven't looked at what happens then.

I'd never seen that: shell:startup  
It gives me an empty folder: C:\Users\Norm\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup

As usual there are always > 1 places and ways on Windows.

The files in this folder are executed when the system starts:
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp

I have a shortcut to a jar file there.

when I installed Java 11 and uninstalled older versions it broke.

What did they change?  
I've noticed several changes over the years with where a java install places files and what it changes in the windows registry.  I've often had to spend many hours going around fixing what doesn't work with the new install.
One of the constant problems is I have a custom entry for the jar extension that gives me a menu of choices on a right click.  I quickly learned to rename the jar entry to jar_Mine and set the .jar entry to refer to that.  Every java install rewrites the .jar entry requiring me to manually reset it and put the new entries in my entry.

I'm glad you got it to work.
Happy programming.

The code should test if there are any args by checking that args.length is > 0.  If there are no args, print a message to the user about what needs to be provided.
Another solution is to provide a default value by assigning a new value to args after line 4:     if(args.length == 0) {               // test if any args passed in         args = new String[] {"5"};        // provide a default arg value of "5"      }

The leading " (before the C) was left off.

Try this as the command in a command prompt window in the folder with the Bucky.java file:
"C:\Program Files\Java\jdk1.8.0_191\bin\javac.exe"   Bucky.java

You should not have any files in or do any work from the JDK's bin folder.

How do I do this exactly?

Here is a link to the JavaFX API doc: https://docs.oracle.com/javase/8/javafx/api/
At the top of the page click on the INDEX link, then click on G for the first letter of the method, search for the method: getScene, then click on the link for that method and read its API doc.

Or if you know the name of the class that getScene is in, find its name in the left hand window, click on it and then scan down to the API doc for the getScene method.

Did you look at the API for getScene to see when it returns a null value?

Did you look at the API for getScene to see when it returns a null value?

Have you tried debugging by adding a print statement after line 1 that prints the value of c?

I don't know what is wrong with your setup of Eclipse.  I just imported the extracted files from the downloaded zip file and was able to compile and run the app in my Android VM running on Oracle.

In Eclipse Did you run the Window/Android SDK Manager to get the android bits and pieces needed?

Can you copy the text of the error messages and paste it here?