Nullness conventions for a Java service: JSpecify @NullMarked on every package-info, non-null by default, mark exceptions @Nullable. Use when adding a package, a field, or a parameter, or when the build fails on a nullness error. The annotations are language-level; the enforcement (NullAway at ERROR on main sources, off for tests) is wired by the build (build-maven-quality). Fix the nullness, do not suppress it.
