NullPointerException in JRE 8 Font

[joelchen]

This Stack Overflow question and answer describes the issue. It only happens in JRE 8 but not in JRE 7.

[yosifkit]

I am not sure we would want to change away from the -headless packages. Why not just use the jdk versions, or extend the jre image in your Dockerfile and install the non-headless package?

[md5]

I'd like to see a test case to reproduce this. It sounds like the JRE is not running actually in headless mode.

[md5]

I was able to reproduce this: https://gist.github.com/md5/7fb07efafee3802da457

It looks like installing libfontconfig1 is a workaround (see the gist).

[yosifkit]

@md5, what do you suggest? Do you think we should add libfontconfig1 to the jre image or should we just point out that a user may need to add libs like this to their images?

[tianon]

Alternatively, could this be considered a missing dependency on the Debian package, or is this strictly something users are supposed to be able to handle from their PoV?

[md5]

I think what @tianon said is correct. This seems to be a missing dependency that should be fixed at the Debian level. I don't have time at the moment to investigate why this may have changed between openjdk-7-jre-headless and openjdk-8-jre-headless or to report it to debian-java@lists.debian.org, but I think that's what needs to happen.

The problem I see with simply adding libfontconfig1 is that without determining the root cause of why it's no longer being installed, it's quite likely that there could be other missing libraries that we don't know about yet that are waiting to crop up. Still, if it's enough of an issue for enough people, adding the libfontconfig1 package seems like a pretty unobtrusive move.

One suspicion I have is that something moved from a dependency to a "recommends", resulting in a bunch of packages being dropped. I'm also wondering whether something might have happened during the Jessie backport process to mess up the dependencies.

[yosifkit]

As far as I can tell, this is a packaging issue. Here are the depends that get libfontconfig1 for java 7 and 8:

openjdk-7-jre-headless -> libfontconfig1
# it is a direct dependency

openjdk-7-jre -> libfontconfig1
# also has longer paths to require libfontconfig1

openjdk-8-jre-headless -> # no fontconfig

openjdk-8-jre -> libatk-wrapper-java-jni -> libcairo2 -> libfontconfig1
# the shortest path to require it

[joelchen]

I have just filed a bug report with Debian.

[md5]

Thanks @joelchen! 👍

[md5]

@tianon @yosifkit What do you guys think of putting in a temporary fix for this, since there doesn't seem to be much movement on the Debian front.

I just got an error report for the jetty image for this same issue: appropriate/docker-jetty#15.

[yosifkit]

Sounds fine to me.

[tianon]

@md5 totally throwing that in now unless you beat me to it 😉

[md5]

@tianon I was thinking about creating a PR when I got back from lunch, but there's no need now. Thanks.

[tianon]

Sorry, I got a little antsy. 😇

[joelchen]

Thanks @md5, @tianon, and @yosifkit! 👍