How can I use a specific version of OpenJDK to build a package?
Instead of a build-dependency on default-jdk, you can build-depend on openjdk-8-jdk or openjdk-11-jdk. Then you have to make sure the JAVA_HOME points to your specific version and not to the default one. You can achieve that by adding
to debian/rules in case you are building the package on amd64.
This is useful for debugging build failures with a non-default JDK. Not build-depending on default-jdk should be avoided though unless there is a very good reason. Otherwise it would make transitions to newer JDK versions more difficult.