The current version Apache Directory Studio, 2.0.0-M13, is built on Oracle Java 8. It can be made to run on Java 9, but does not work on either Oracle Java 10 or OpenJDK 10.
To specify that it use OpenJDK 8 on Linux, edit ApacheDirectoryStudio.ini to add the following lines to the top of the file:
-vm
/usr/lib/jvm/java-8-openjdk-amd64/bin/java