The only two alternatives I see is to add `@Nonnul...

# intellij

[martinb]

The only two alternatives I see is to add `@Nonnull`/`@Nullable` directly in JDK jars, or to create inline extension methods such as inline fun Matcher.group_(i: Int):String? = this.group(i). The first solution is not realistic, and the second solution requires us to always call matcher.group_(1).length() instead of matcher.group(1).length()