Various pattern-matching operations could be made simpler with some lambda-friendly methods.

Examples:

1) Extracting data from a String

Pattern p = Pattern.compile("\d*, (\d*), (\d*)");
for (String s : lines) {
   p.match(str, r -> System.out.println(r.group(1) + r.group(2)));
}

(The lambda operates on a MatchResult. It could be a Consumer or a Function. It is not invoked if the string does not match.)

2) Getting a Stream of matches from a String

Pattern p = Pattern.compile("(\d)*");
lines.stream().flatMap(line -> p.findAll(line)).map(r -> r.group(1)).forEach(System.out::println);

(The result of 'findAll' is a Stream<MatchResult>.)

3) Performing find-replace on a String

Pattern p = Pattern.compile("<(.*)>")
p.replace(someString, r -> "(" + r.group(1) + ")")

Note that all of these also make sense as methods of String.

More discussion is here: http://mail.openjdk.java.net/pipermail/core-libs-dev/2014-November/029769.html