public static Exprent parseAnnotationElement(DataInputStream data, ConstantPool pool) throws IOException {
    int tag = data.readUnsignedByte();

    switch (tag) {
      case 'e' -> { // enum constant
        String className = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
        String constName = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
        FieldDescriptor descr = FieldDescriptor.parseDescriptor(className);
        return new FieldExprent(constName, descr.type.getValue(), true, null, descr, null);
      }
      case 'c' -> { // class
        String descriptor = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
        VarType type = FieldDescriptor.parseDescriptor(descriptor).type;

        String value = switch (type.getType()) {
          case CodeConstants.TYPE_OBJECT -> type.getValue();
          case CodeConstants.TYPE_BYTE -> byte.class.getName();
          case CodeConstants.TYPE_CHAR -> char.class.getName();
          case CodeConstants.TYPE_DOUBLE -> double.class.getName();
          case CodeConstants.TYPE_FLOAT -> float.class.getName();
          case CodeConstants.TYPE_INT -> int.class.getName();
          case CodeConstants.TYPE_LONG -> long.class.getName();
          case CodeConstants.TYPE_SHORT -> short.class.getName();
          case CodeConstants.TYPE_BOOLEAN -> boolean.class.getName();
          case CodeConstants.TYPE_VOID -> void.class.getName();
          default -> throw new RuntimeException("invalid class type: " + type.getType());
        };
        return new ConstExprent(VarType.VARTYPE_CLASS, value, null);
      }
      case '[' -> { // array
        List<Exprent> elements = Collections.emptyList();
        int len = data.readUnsignedShort();
        if (len > 0) {
          elements = new ArrayList<>(len);
          for (int i = 0; i < len; i++) {
            elements.add(parseAnnotationElement(data, pool));
          }
        }

        VarType newType;
        if (elements.isEmpty()) {
          newType = new VarType(CodeConstants.TYPE_OBJECT, 1, "java/lang/Object");
        }
        else {
          VarType elementType = elements.get(0).getExprType();
          newType = new VarType(elementType.getType(), 1, elementType.getValue());
        }

        NewExprent newExpr = new NewExprent(newType, Collections.emptyList(), null);
        newExpr.setDirectArrayInit(true);
        newExpr.setLstArrayElements(elements);
        return newExpr;
      }
      case '@' -> { // annotation
        return parseAnnotation(data, pool);
      }
      default -> {
        PrimitiveConstant cn = pool.getPrimitiveConstant(data.readUnsignedShort());
        return switch (tag) {
          case 'B' -> new ConstExprent(VarType.VARTYPE_BYTE, cn.value, null);
          case 'C' -> new ConstExprent(VarType.VARTYPE_CHAR, cn.value, null);
          case 'D' -> new ConstExprent(VarType.VARTYPE_DOUBLE, cn.value, null);
          case 'F' -> new ConstExprent(VarType.VARTYPE_FLOAT, cn.value, null);
          case 'I' -> new ConstExprent(VarType.VARTYPE_INT, cn.value, null);
          case 'J' -> new ConstExprent(VarType.VARTYPE_LONG, cn.value, null);
          case 'S' -> new ConstExprent(VarType.VARTYPE_SHORT, cn.value, null);
          case 'Z' -> new ConstExprent(VarType.VARTYPE_BOOLEAN, cn.value, null);
          case 's' -> new ConstExprent(VarType.VARTYPE_STRING, cn.value, null);
          default -> throw new RuntimeException("invalid element type!");
        };
      }
    }
  }
public static Exprent parseAnnotationElement(DataInputStream data, ConstantPool pool)