I've had the same problem, which also doesn't seem fixable by previous answers; this appears to be a simple case that OpenJDK 10 on Ubuntu cannot run the current version of Minecraft with the 1.6.89-j Launcher.
Luckily, OpenJDK 8 is still available in the Universe repository, and if your system has been upgraded to Ubuntu 18.04 then it will probably already be installed. If not, install the openjdk-8-jre
package.
Try starting the Launcher/game with /usr/lib/jvm/java-8-openjdk-amd64/bin/java
instead of just java
.
Unfortunately OpenJDK 8 will soon reach end-of-life for support, so you need to be aware of that.
Additionally the openjdk-11
packages offered by Ubuntu actually contain OpenJDK 10 at the moment, and are intended to silently upgrade to the real OpenJDK 11 when that is released.
See https://lists.ubuntu.com/archives/ubuntu-release/2018-February/004275.html for more information on the versions and support periods.