tweak@AmigaBuntu:~$ sudo apt install openjdk-9-jdk
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  openjdk-9-demo openjdk-9-source visualvm
The following NEW packages will be installed:
  openjdk-9-jdk
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/16.6 kB of archives.
After this operation, 58.4 kB of additional disk space will be used.
(Reading database ... 403847 files and directories currently installed.)
Preparing to unpack .../openjdk-9-jdk_9~b114-0ubuntu1_amd64.deb ...
Unpacking openjdk-9-jdk:amd64 (9~b114-0ubuntu1) ...
dpkg: error processing archive /var/cache/apt/archives/openjdk-9-jdk_9~b114-0ubuntu1_amd64.deb (--unpack):
 trying to overwrite '/usr/lib/jvm/java-9-openjdk-amd64/include/linux/jawt_md.h', which is also in package openjdk-9-jdk-headless:amd64 9~b114-0ubuntu1
Errors were encountered while processing:
 /var/cache/apt/archives/openjdk-9-jdk_9~b114-0ubuntu1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
tweak@AmigaBuntu:~$