As part of the changes for the jigsaw module system in Java 9, the
java packages available to the boot classloader are now a subset of
the the full java distribution. This means that classes loaded via the
boot classloader cannot access any classes outside of that subset.
In the boot classloader only the java.base module is available. For a complete list of module/package listings see http://cr.openjdk.java.net/~mr/jigsaw/ea/module-summary.html
Clojure itself uses java.sql.Timestamp in clojure.instant to provide print-method and print-dup implementations for java.sql.Timestamp.
This can be seen with (using Clojure 1.4.0 or higher, and a early-access build
of Java 9, most recently tested with 9-ea+147):
Proposed: If java.sql.Timestamp is not available, do not load instant.clj or install it in the default data readers.
Screener Notes: This looks correct and does not break normal usage. Should be tested in the bootclasspath scenarios people have problems with.