I have following custom ConstraintValidator:

public class FileNamePatternValidator implements ConstraintValidator<FilenamePattern, FileUpload> {

   String regex;

   @Override
   public void initialize(FilenamePattern constraintAnnotation) {
      regex = constraintAnnotation.regex();
   }

   @Override
   public boolean isValid(FileUpload fileUpload, ConstraintValidatorContext context) {

      if (fileUpload == null) {
         return true;
      }

      // Check if filename of fileUpload is correct

      return true;
   }
}

Now I was wondering if I put this FilenamePattern on a parameter inside a method like this

@POST
@Consumes(MediaType.MULTIPART_FORM_DATA)
@Path("{xy}")
public Response saveXY(
      @PathParam("xy")
      String xy,
      @RestForm("txtFile")
      @FilenamePattern(regex = "^[a-zA-Z_\.]+\.txt$")
      FileUpload txtFile
) {
   // Do something with file
   return Response.ok().build();
}

which can be called in parallel. Does this mean that I do not need to worry about thread safety of my ConstrainValidator. Because if jakarta ee handles ConstraintValidator inside container as singletons then field String regex; is shared resource and I need to save regex value as ThreadLocal.