Behaviour of calling matches() and then find() doesn't match java.util.regex

[cushon]

In the following example, the behaviour of re2j doesn't match the behaviour of java.util.regex.

With java.util.regex, calling matches() and then find() advances to a second match (which doesn't exist), so it throws an IllegalStateException.

public class T {
  public static void main(String[] args) {
    String pattern = "([1-5][0-9]{2})-([1-5][0-9]{2})";
    String input = "201-299";
    {
      System.err.println("> re2j");
      try {
        var p = com.google.re2j.Pattern.compile(pattern);
        var m = p.matcher(input);
        if (m.matches()) {
          m.find();
          System.err.println(
              "match: " + Integer.parseInt(m.group(1)) + " - " + Integer.parseInt(m.group(2)));
        }
      } catch (Exception e) {
        System.err.println(e.getClass() + " " + e.getMessage());
      }
    }
    {
      System.err.println("> java.util.regex");
      try {
        var p = java.util.regex.Pattern.compile(pattern);
        var m = p.matcher(input);
        if (m.matches()) {
          m.find(); // java.util.regex reports a match if the extra call to find() is removed
          System.err.println(Integer.parseInt(m.group(1)) + " - " + Integer.parseInt(m.group(2)));
        }
      } catch (Exception e) {
        System.err.println(e.getClass() + " " + e.getMessage());
      }
    }
  }
}

> re2j
match: 201 - 299
> java.util.regex
class java.lang.IllegalStateException No match found