Fix virtual thread builder interop (#1810)

CHANGELOG.md

@@ -7,6 +7,10 @@ A preview of the next release can be installed from
 
 [Babashka](https://github.com/babashka/babashka): Native, fast starting Clojure interpreter for scripting
 
+## Unreleased
+
+- Fix virtual `ThreadBuilder` interop
+
 ## 1.12.199 (2025-04-18)
 
 - [#1806](https://github.com/babashka/babashka/issues/1806): Add `cheshire.factory` namespace ([@lread](https://github.com/lread))

src/babashka/impl/classes.clj

@@ -340,6 +340,7 @@
           java.lang.Throwable
           java.lang.ThreadLocal
           java.lang.Thread$UncaughtExceptionHandler
+          java.lang.Thread$Builder
           java.lang.UnsupportedOperationException
           java.lang.ref.WeakReference
           java.lang.ref.ReferenceQueue
@@ -808,7 +809,8 @@
                                    (instance? org.jsoup.nodes.Element v)
                                    org.jsoup.nodes.Element
                                    ;; keep commas for merge friendliness
-                                   )]
+                                   (instance? java.lang.Thread$Builder v)
+                                   java.lang.Thread$Builder)]
                      ;; (prn :res res)
                      res)))
         m (assoc m (list 'quote 'clojure.lang.Var) 'sci.lang.Var)

test/babashka/interop_test.clj

@@ -18,7 +18,10 @@
          (bb nil (pr-str '(do
                             (def t (Thread. (fn [])))
                             (def vt (Thread/startVirtualThread (fn [])))
-                            [(.isVirtual t) (.isVirtual vt)]))))))
+                            [(.isVirtual t) (.isVirtual vt)])))))
+  (is (bb nil (pr-str '(instance?
+                        java.util.concurrent.Executor
+                        (java.util.concurrent.Executors/newThreadPerTaskExecutor (-> (Thread/ofVirtual) (.name "fusebox-thread-" 1) (.factory))))))))
 
 (deftest domain-sockets-test
   (is (= :success (bb nil (slurp "test-resources/domain_sockets.bb")))))