We have seen how we need to escape all the special regex metacharacters to be able to match them literally.

The Java regex engine provides special escape sequences, Q and E, for this purpose. Any string that is wrapped between Q and E looses interpretation of all the regex metacharacters in the wrapped string.

For example, to write a regex that matches a string ^*+., we can avoid all escaping and use this regex:

Q^*+.E

Note that there must not be any character escaping between Q and E sequences.

To match an input string, "[a-z0-9]", we can write our regex as follows:

Q[a-z0-9]E

Java provides a convenient method to return a literal pattern sting for the given string called Pattern.quote(String). We will learn about this method in Chapter 5, Introduction to Java Regular Expressions APIs - Pattern and Matcher Classes, of the book.