Package com.uber.nullaway.annotations

Annotation Type MonotonicNonNull

@Retention(CLASS)
@Target(FIELD)
public @interface MonotonicNonNull

Indicates that once the field becomes non-null, it never becomes null again. Inspired by the identically-named annotation from the Checker Framework. A @MonotonicNonNull field can only be assigned non-null values. The key reason to use this annotation with NullAway is to enable reasoning about field non-nullness in nested lambdas / anonymous classes, e.g.:

 class Foo {
   @MonotonicNonNull Object theField;
   void foo() {
     theField = new Object();
     Runnable r = () -> {
       // No error, NullAway knows theField is non-null after assignment
       theField.toString();
     }
   }
 }