Since String.split() works with regular expressions, this snippet:
String s = "str?str?argh";
s.split("r?");
... yields: [, s, t, , ?, s, t, , ?, a, , g, h]
What's the most elegant way to split this String on the r? sequence so that it produces [st, st, argh]?
EDIT: I know that I can escape the problematic ?. The trouble is I don't know the delimiter offhand and I don't feel like working this around by writing an escapeGenericRegex() function.
A general solution using just Java SE APIs is:
String separator = ...
s.split(Pattern.quote(separator));
The quote method returns a regex that will match the argument string as a literal.
Commenters have noted that there are scenarios in which using Pattern.compile and caching the resulting Matcher has performance benefits. But the counter to that is that there are scenarios where it is not beneficial (or the benefit is insignificant). And in a multi-threaded application, sharing a Matcher across multiple threads is potentially problematic because Matcher is not thread-safe. The bottom line is that discussion of using Pattern.compile (or not) is a red herring in the context of the question asked.