Method nextNull

src/main/java/com/google/gson/stream/JsonReader.java:503–514

Consumes the next token from the JSON stream and asserts that it is a literal null. @throws IllegalStateException if the next token is not null or if this reader is closed.

()

   *     reader is closed.
   */
  public void nextNull() throws IOException {
    quickPeek();
    if (value == null || token == JsonToken.STRING) {
      throw new IllegalStateException("Expected null but was " + peek());
    }

    if (!value.equalsIgnoreCase("null")) {
      throw new IllegalStateException("Not a null: " + value);
    }

    advance();
  }

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