Nullability

Composite Recipes

Recipes that include further recipes, often including the individual recipes below.

• Compose JSpecify best practices (intra-body nullability inference)
• Make a codebase null-safe

Recipes

• Add @MonotonicNonNull to a lazily-initialized field
• Add @MonotonicNonNull to an uninitialized field
• Add @NullMarked to every package
• Add @NullMarked to package-info.java for an allowlist of packages
• Add @Nullable to Java returns from Kotlin call sites
• Add @Nullable to a field assigned a nullable value
• Add @Nullable to a functional-interface return type argument fed a null-returning lambda
• Add @Nullable to a method that can return null
• Add @Nullable to a mismatched generic type argument
• Add @Nullable to array element types that can hold null
• Add @Nullable to collection and map type arguments that hold null elements
• Add @Nullable to fields that can hold null
• Add @Nullable to generated Thrift getters of optional fields
• Add @Nullable to method parameters that can receive null
• Add @Nullable to methods that can return null
• Add a @Contract nullness contract to a validation helper
• Add a @Nullable upper bound to a pass-through type parameter fed a null-returning lambda
• Align override nullability with the supertype
• Extract a repeated @Nullable invocation into a local variable
• Hoist a guarded @Nullable field read into a local variable
• Make a nullable Boolean condition null-safe with Boolean.TRUE.equals(...)
• Migrate @NonNullApi/ParametersAreNonnullByDefault to JSpecify @NullMarked
• Move a leading @Nullable to the type-use position
• Propagate @Nullable across override relationships
• Relax Optional.of to Optional.ofNullable on nullable values
• Relocate a misplaced leading @Nullable on a primitive array to the array reference
• Remove a provably-dead if (x == null) guard
• Remove a redundant @NonNull annotation under @NullMarked
• Remove a redundant declaration-position @Nullable on a method return
• Replace @Nullable with @MonotonicNonNull on a lazily-initialized field
• Replace nullable x.toString() with String.valueOf(x)
• Return an empty collection instead of null
• Route a guarded raw accessor through its present Optional
• Wrap a nullable for-each iterable in requireNonNull
• Wrap nullable arguments passed to non-null parameters in requireNonNull
• Wrap nullable dereferenced values in requireNonNull
• Wrap nullable switch selectors in requireNonNull
• Wrap nullable thrown expressions in requireNonNull
• Wrap nullable values that are auto-unboxed in requireNonNull