### Question:
NotNullValidator implements ConstraintValidator<NotNull, Object> { public boolean isValid(Object object, ConstraintValidatorContext constraintValidatorContext) { return object != null; }  void initialize(NotNull parameters); boolean isValid(Object object, ConstraintValidatorContext constraintValidatorContext);  }### Answer:
@Test public void testIsValid() { NotNullValidator constraint = new NotNullValidator(); assertFalse( constraint.isValid( null, null ) ); assertTrue( constraint.isValid( new Object(), null ) ); }