Do I always need to escape metacharacters in a string that is not a “literal”?

Question

It seems that having a string that contains the characters { or } is rejected during regex processing. I can understand that these are reserved cha

Answer 1

You don't need any extra code, just the \Q and \E constructs, as documented in Java's Pattern class.

For example, in the following code:

String foobar = "crazyPassword=f()ob@r{}+";
Pattern regex = Pattern.compile("\\Q" + foobar "\\E");

the pattern would compile and foobar's special characters would not be interpreted as regex characters. See demo here.

The only thing that it won't match is where the input contains a literal \E. If you need to solve that problem too, just let me know in a comment and I'll edit to add that.