Question

"\"a".matches("a") returns false. What’s going on here?

Answer 1

The matches method expects the entire string to match, not just a match to exist somewhere inside the target string.

This, on the other hand, returns true, because it lets the string contain anything before or after the match:

"\"a".matches(".*a.*")

Another way to look for a match anywhere in the string is by using Pattern directly:

if (Pattern.compile("a").matcher("\"a").find()) {
    ...
}