Method nextLong

src/main/java/com/google/gson/stream/JsonReader.java:555–578

Returns the JsonToken#NUMBER long value of the next token, consuming it. If the next token is a string, this method will attempt to parse it as a long. If the next token's numeric value cannot be exactly represented by a Java long, this method throws. @throws IllegalStateException i

()

   *     as a number, or exactly represented as a long.
   */
  public long nextLong() throws IOException {
    quickPeek();
    if (value == null) {
      throw new IllegalStateException("Expected a long but was " + peek());
    }

    long result;
    try {
      result = Long.parseLong(value);
    } catch (NumberFormatException ignored) {
      double asDouble = Double.parseDouble(value); // don't catch this NumberFormatException
      result = (long) asDouble;
      if (result != asDouble) {
        throw new NumberFormatException(value);
      }
    }

    if (result >= 1L && value.startsWith("0")) {
      throw new NumberFormatException("JSON forbids octal prefixes: " + value);
    }

    advance();
    return result;
  }

  /**
   * Returns the {@link JsonToken#NUMBER int} value of the next token,