code: public DateTimeFormatterBuilder appendLiteral(String literal) {
          Jdk8Methods.requireNonNull(literal, "literal");
          if (literal.length() > 0) {
              if (literal.length() == 1) {
                  appendInternal(new CharLiteralPrinterParser(literal.charAt(0)));
              } else {
                  appendInternal(new StringLiteralPrinterParser(literal));
              }
          }
          return this;
      }
docs: Appends a string literal to the formatter.
  <p>
  This string will be output during a print.
  <p>
  If the literal is empty, nothing is added to the formatter.
  
  @param literal  the literal to append, not null
  @return this, for chaining, not null