diff --git a/.circleci/script/gen_ci.clj b/.circleci/script/gen_ci.clj
index 95da8d94..6ae191af 100644
--- a/.circleci/script/gen_ci.clj
+++ b/.circleci/script/gen_ci.clj
@@ -101,7 +101,6 @@
         "export BABASHKA_FEATURE_JDBC=true
 export BABASHKA_FEATURE_POSTGRESQL=true
 script/test\nscript/run_lib_tests")
-      (run "Run as lein command" ".circleci/script/lein")
       (run
         "Create uberjar"
         "mkdir -p /tmp/release
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b64257aa..3b1c42e5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -60,9 +60,6 @@ jobs:
           script/test
           script/run_lib_tests
 
-      - name: Run as lein command
-        run: echo '{:a 1}' | lein bb '(:a *in*)'
-
       - name: Build uberjar
         run: |
           mkdir -p /tmp/release
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index 4789e11f..01bff589 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -255,6 +255,10 @@
     jdk.internal.net.http.websocket.BuilderImpl
     jdk.internal.net.http.websocket.WebSocketImpl])
 
+(def thread-builder
+  (try (Class/forName "java.lang.Thread$Builder")
+       (catch Exception _ nil)))
+
 (def classes
   `{:all [clojure.lang.ArityException
           clojure.lang.BigInt
@@ -340,7 +344,8 @@
           java.lang.Throwable
           java.lang.ThreadLocal
           java.lang.Thread$UncaughtExceptionHandler
-          java.lang.Thread$Builder
+          ~@(when thread-builder
+              '[java.lang.Thread$Builder])
           java.lang.UnsupportedOperationException
           java.lang.ref.WeakReference
           java.lang.ref.ReferenceQueue
@@ -808,9 +813,11 @@
                                    java.lang.Throwable
                                    (instance? org.jsoup.nodes.Element v)
                                    org.jsoup.nodes.Element
+                                   (and thread-builder
+                                        (instance? thread-builder v))
+                                   thread-builder
                                    ;; 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)