Yes, very likely a network issue.

This error is caused by a network issue (the "peer" being the external browser sending requests to Ubooquity).

It happens when the connection is lost during a transfer or when the browser cancels it.

Since this is network related, it should affect both books and comics. I don't know why they behave differently.

It's perhaps due to the fact that book chapters are much smaller files that comic pages.

Do you have the same problem when downloading the full book/comic instead of reading it online ?

If you do, this is really a network issue.

Ubooquity does not have any external dependency to external libraries, it's full Java.

If you are running it on Linux, does your user have writing permission on this "/config" folder ?

Not fixed yet.

The fix will be announced in the release notes when it's done.

Interesting, thanks !

Given the limitations (zip only and performances), I don't know if trying to build something efficient using remote resources would be really doable, but at least now I know there is a possibility.

I tempted to try to automate certificate management using Acme4J.

I don't know when or even if I'll do it, but manually managing certificates sure is painful.

Great !

I'll update the FAQ and the download page so that users know they need a really recent version of Java.

Sure:

tom 'at' vaemendis 'dot' net

Another idea: try to update to the latest version of Java 8 (you are currently using 1.8.0_60, the latest is 1.8.0_92).

I'm not sure of it, but the missing library (javalcms) seems to have been embedded in recent versions only.

Managing permissions on subdirectories would have added too much complexity, both on code and user side.

It just wasn't worth the trouble.