code: private void computeDefaultSerializableFields(DocEnv env,
                                                    ClassSymbol def,
                                                    ClassDocImpl cd) {
          for (Symbol sym : def.members().getSymbols(NON_RECURSIVE)) {
              if (sym != null && sym.kind == VAR) {
                  VarSymbol f = (VarSymbol)sym;
                  if ((f.flags() & Flags.STATIC) == 0 &&
                      (f.flags() & Flags.TRANSIENT) == 0) {
                      //### No modifier filtering applied here.
                      FieldDocImpl fd = env.getFieldDoc(f);
                      //### Add to beginning.
                      //### Preserve order used by old 'javadoc'.
                      fields.prepend(fd);
                  }
              }
          }
      }
docs: /*
  Compute default Serializable fields from all members of ClassSymbol.
  
  Since the fields of ClassDocImpl might not contain private or
  package accessible fields, must walk over all members of ClassSymbol.