Source: openjdk-9 Severity: normal The jmod files installed under the /usr/lib/jvm/java-9-openjdk-amd64/jmods/ directory by openjdk-9-jre-headless are meant to be used at compile time or link time but not at run time. Upstream ships them as part of the JDK and not the JRE. So we should install them from openjdk-9-jdk-headless.