$ javac --enable-preview --release 26 StructuredScope26.java      (JDK 26)
exit=0

$ javac --enable-preview --release 27 StructuredScope26.java      (JDK 27)
StructuredScope26.java:12: error: wrong number of type arguments; required 3
        try (StructuredTaskScope<String, List<String>> scope =
                                ^
StructuredScope26.java:17: error: cannot find symbol
        } catch (StructuredTaskScope.FailedException e) {
                                    ^
  symbol:   class FailedException
  location: interface StructuredTaskScope
StructuredScope26.java:19: error: cannot find symbol
        } catch (StructuredTaskScope.TimeoutException e) {
                                    ^
  symbol:   class TimeoutException
  location: interface StructuredTaskScope
3 errors
exit=1