Arduino IDE will not open on Linux Ubuntu 18.04

[hellocaio]

Suddently Arduino IDE 1.8.6 will not start. I've been working on it without problems for days until now. I added WiFiManager library into my libraries using the Library Manager, then I tried to compile it but it threw an error saying "Can't find <WifiManager.h>" even thought I just had added it. Then I closed the IDE to restart it but I haven't been able to open it again. The spash screen shows and it closes right after showing "Preparing boards...".

Here is the error that I get:

:~/arduino-1.8.6$ ./arduino
Picked up JAVA_TOOL_OPTIONS: 
Error parsing library.index:Unexpected end-of-input: expected close marker for Object (start marker at [Source: (FileInputStream); line: 45890, column: 5])
 at [Source: (FileInputStream); line: 45901, column: 5664]
 at [Source: (FileInputStream); line: 45901, column: 7] (through reference chain: com.fasterxml.jackson.module.mrbean.generated.cc.arduino.contributions.libraries.LibrariesIndex["libraries"]->java.util.ArrayList[2164])
java.lang.NullPointerException
	at cc.arduino.contributions.libraries.LibrariesIndexer.rescanLibraries(LibrariesIndexer.java:140)
	at cc.arduino.contributions.libraries.LibrariesIndexer.setLibrariesFolders(LibrariesIndexer.java:109)
	at processing.app.BaseNoGui.onBoardOrPortChange(BaseNoGui.java:677)
	at processing.app.Base.onBoardOrPortChange(Base.java:1313)
	at processing.app.Base$12.actionPerformed(Base.java:1540)
	at processing.app.Base.filterVisibilityOfSubsequentBoardMenus(Base.java:1579)
	at processing.app.Base.access$000(Base.java:83)
	at processing.app.Base$11.actionPerformed(Base.java:1512)
	at processing.app.Base.rebuildBoardsMenu(Base.java:1490)
	at processing.app.Base.<init>(Base.java:267)
	at processing.app.Base.main(Base.java:145)

I tried removing and installing the Arduino IDE multiple times and rebooting the system. Any more ideas?

[PaulStoffregen]

Duplicate of #7937. Fixed by #7964.

To recover, either download and run the 2nd arduinobot build on #7964. Or run this in a terminal

rm ~.arduino15/library_index.json

You may need to open the library manager twice to see the correct library list.

[hellocaio]

Sorry for the duplicate. I did search, but the error is so generic that I got many unrelated results. @PaulStoffregen , that worked great! Thanks man! I wasn't aware of the hidden .arduino15, I had looked for a json file. Thanks a lot!

[per1234]

This same variant ("Unexpected end-of-input") of #7937 was reported on the Arduino forum (http://forum.arduino.cc/index.php?topic=565839) and I got that user to send me the problematic library_index.json file. I couldn't find anything wrong with the file they provided and I had no problems starting Arduino IDE 1.8.6 with that file in place. However, the workaround of removing the problematic library_index.json did solve it for them so I believe that, although this error is a little different than #7937, #7964 will still solve it.

[PaulStoffregen]

That forum user is yet another case, right? Using Windows & this one was Linux.

Really looking forward to a 1.8.7 release....

[hellocaio]

I don't know if this helps but my initial error was:

Gtk-Message: Failed to load module "canberra-gtk-module"

It took me to this thread and some people got the issue resolved by installing the modules in the answer. I installed the modules and then the error became the one I showed in my original post above.

[cmaglie]

Really looking forward to a 1.8.7 release....

we'll release Tuesday Sep,11

[MasterCATZ]

Ubuntu 18.04 LTS ,

/arduino-1.8.8$ ./arduino
Picked up JAVA_TOOL_OPTIONS:
mmap failed for CEN and END part of zip file
Error occurred during initialization of VM
java/lang/ClassNotFoundException: error in opening JAR file

[facchinm]

@MasterCATZ it looks like you need to redownload the IDE zip since it's corrupt (make sure the checksum matches this