Source: postgis-java Version: 1:2.2.1-5 Severity: serious postgis-java build depends on openjdk-8-jdk-headless, which is not expected to be part of the buster release.
Build-Depends-Indep: default-jdk-headless, openjdk-8-jdk-headless | java7-sdk-headless, Java 7 is even in jessie, I wonder whether the second line here could just be removed with default-jdk-headless already covering the required JDK in all cases.