FULL PRODUCT VERSION :
java version "1.8.0_77"
Java(TM) SE Runtime Environment (build 1.8.0_77-b03)
Java HotSpot(TM) 64-Bit Server VM (build 25.77-b03, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
[root@6b8ab63d2271 /]# uname -a
Linux 6b8ab63d2271 4.6.0-0.bpo.1-amd64 #1 SMP Debian 4.6.3-1~bpo8+1 (2016-07-13) x86_64 x86_64 x86_64 GNU/Linux

[root@6b8ab63d2271 /]# cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)

EXTRA RELEVANT SYSTEM CONFIGURATION :
Host System: Debian Jessie
Runs Docker version 1.12.1, build 23cf638 started with --storage-driver=overlay
Error does occur inside of the docker container which is centos 7

A DESCRIPTION OF THE PROBLEM :
When running java inside of a docker container which root fs is an overlayfs

e.g. from mount: overlay on / type overlay (rw,relatime,lowerdir=/var/lib/docker/overlay/7f380aa866f1411985b0e3d9533e89f0907e11adb81c2c1e20a5733fd3112f33/root,upperdir=/var/lib/docker/overlay/58f650cc4005e9becf01c20b2d8144a372115d11add9e70774322232e3fef590/upper,workdir=/var/lib/docker/overlay/58f650cc4005e9becf01c20b2d8144a372115d11add9e70774322232e3fef590/work)

And accessing a file like /home/someuser/somefile.txt

An Exception will be thrown.


A very similar Case seems to exist with btrfs and subvolumes:
https://github.com/elastic/elasticsearch/issues/14337 and
https://github.com/elastic/elasticsearch/issues/12018


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start a docker container where dockerd was started with --overlfay and try to access files via Files.getFileStore(path)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The Result should be / (if there is no other mount)
ACTUAL -
java.io.IOException: Mount point not found

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.io.IOException: Mount point not found
        at sun.nio.fs.LinuxFileStore.findMountEntry(LinuxFileStore.java:91)
        at sun.nio.fs.UnixFileStore.<init>(UnixFileStore.java:65)
        at sun.nio.fs.LinuxFileStore.<init>(LinuxFileStore.java:44)
        at sun.nio.fs.LinuxFileSystemProvider.getFileStore(LinuxFileSystemProvider.java:51)
        at sun.nio.fs.LinuxFileSystemProvider.getFileStore(LinuxFileSystemProvider.java:39)
        at sun.nio.fs.UnixFileSystemProvider.getFileStore(UnixFileSystemProvider.java:368)
        at java.nio.file.Files.getFileStore(Files.java:1461)
        at MyMain.main(MyMain.java:8)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class MyMain {

public static void main(String[] args) throws IOException {
System.out.println(Files.getFileStore(Paths.get(args[0])));
}
}

---------- END SOURCE ----------