org.checkerframework.framework.qual

Annotation Type Bottom

@SubtypeOf(value={})
 @Target(value={TYPE_USE,TYPE_PARAMETER})
 @TargetLocations(value={EXPLICIT_LOWER_BOUND,EXPLICIT_UPPER_BOUND})
public @interface Bottom

A special annotation intended solely for representing the bottom type in the qualifier hierarchy. This qualifier is only used automatically if the existing qualifiers do not have a bottom type. Other type systems could reuse this qualifier instead of introducing their own dedicated bottom qualifier. The programmer would then use methods like ImplicitsTreeAnnotator.addTreeKind(com.sun.source.tree.Tree.Kind, javax.lang.model.element.AnnotationMirror) to add implicit annotations and needs to manually add the bottom qualifier to the qualifier hierarchy.

Note that because of the missing RetentionPolicy, the qualifier will not be stored in bytecode.

Only use this qualifier for very simple type systems. For realistic systems, introduce a top and bottom qualifier that gets stored in bytecode.

See Also:

QualifierHierarchy.getBottomAnnotations()