String.matches() with \n

Question

Why the String::matches method returns false when the string contains \n?

public class AppMain2 {

    public static void main(String[] args) {

        String data1 = "\n  London";    
        System.out.println(data1.matches(".*London.*")); // false
    }    
}

Answer 1

If you want matches to return true, you need to use (?s) or Pattern.DOTALL.

This way . matches any character including \n

System.out.println(data1.matches("(?s).*London.*"));

or:

Pattern pattern = Pattern.compile(".*London.*", Pattern.DOTALL);
System.out.println(data1.matches(pattern));