diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000000..7fcbf6b17a
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,25 @@
+name: Java CI
+
+on: [push]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        jdk: ['8', '11', '17', '19']
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK ${{ matrix.jdk }}
+        uses: actions/setup-java@v2
+        with:
+          java-version: ${{ matrix.jdk }}
+          distribution: 'temurin'
+          cache: maven
+      - name: Build with Maven
+        run: mvn test
+      - name: Configure settings.xml
+        run: |
+          mkdir -p ~/.m2
+          echo "<settings><servers><server><id>clojars</id><username>${{ secrets.CLOJARS_USER }}-clojars</username><password>${{ secrets.CLOJARS_PASSWORD }}</password></server></servers></settings>" > ~/.m2/settings.xml
diff --git a/deps.edn b/deps.edn
new file mode 100644
index 0000000000..1b5a7ea601
--- /dev/null
+++ b/deps.edn
@@ -0,0 +1,38 @@
+;; https://clojure.org/dev/developing_patches#_run_an_individual_test
+{:paths ["test"
+         "target/test-classes"]
+ :deps
+ {org.clojure/clojure {:local/root "."
+                       :deps/manifest :pom} #_{:mvn/version "RELEASE"}
+  org.clojure/test.check {:mvn/version "1.1.1"}
+  org.clojure/test.generative {:mvn/version "1.0.0"}}
+ :aliases
+ {:dbg {:classpath-overrides {org.clojure/clojure "target/classes"}
+        :extra-deps {criterium/criterium {:mvn/version "0.4.4"}}}
+  :cognitest {:extra-deps {io.github.cognitect-labs/test-runner 
+                           {:git/tag "v0.5.0" :git/sha "b3fd0d2"}}
+              :main-opts ["-m" "cognitect.test-runner"]
+              :exec-fn cognitect.test-runner.api/test
+              :exec-args {:dirs ["test"]
+                          :patterns [;; FIXME clojure.test-clojure.ns-libs has a test that is sensitive to loading order
+                                     ;; FIXME clojure.test-clojure.java-interop doesn't seem to work on JDK 17 (untested on others)
+                                     ;; regex ref: https://stackoverflow.com/a/2387072
+                                     "^((?!(clojure.test-clojure.ns-libs|clojure.test-clojure.java-interop)).)*$"
+                                     ]}}
+  :test-example-script {:jvm-opts [;; from build.xml
+                                   "-Dclojure.test-clojure.exclude-namespaces=#{clojure.test-clojure.compilation.load-ns clojure.test-clojure.ns-libs-load-later}"
+                                   "-Dclojure.compiler.direct-linking=true"]
+                        :main-opts ["-e" "(load-file,\"src/script/run_test.clj\")"]}
+  :test-generative-script {:jvm-opts [;; from build.xml
+                                      "-Dclojure.compiler.direct-linking=true"]
+                           :main-opts ["-e" "(load-file,\"src/script/run_test_generative.clj\")"]}
+
+  :kaocha {:extra-deps {lambdaisland/kaocha {:mvn/version "1.60.977"}}
+           :exec-fn kaocha.runner/exec-fn
+           :exec-args {;:watch? true
+                       :tests [{:id          :unit
+                                :test-paths  ["test"]
+                                :ns-patterns [".*"]}]
+                       :reporter kaocha.report/dots
+                       ;; :plugins [:kaocha.plugin/profiling :kaocha.plugin/notifier]
+                       }}}}
diff --git a/src/jvm/clojure/lang/RestFn.java b/src/jvm/clojure/lang/RestFn.java
index f6d844302a..b0c44e6feb 100644
--- a/src/jvm/clojure/lang/RestFn.java
+++ b/src/jvm/clojure/lang/RestFn.java
@@ -4078,7 +4078,7 @@ public Object invoke(Object arg1, Object arg2, Object arg3, Object arg4, Object
                                         Util.ret1(arg16,arg16=null), Util.ret1(arg17,arg17=null), Util.ret1(arg18,arg18=null), 
                                         Util.ret1(arg19,arg19=null), Util.ret1(arg20,arg20=null), ArraySeq.create(args));
 		default:
-			return throwArity(21);
+			return throwArity(20 + args.length);
 		}
 
 }
diff --git a/test/clojure/test_clojure/fn.clj b/test/clojure/test_clojure/fn.clj
index dfd1eaf244..05d2bb2ad5 100644
--- a/test/clojure/test_clojure/fn.clj
+++ b/test/clojure/test_clojure/fn.clj
@@ -53,3 +53,22 @@
     (is (fails-with-cause? clojure.lang.ExceptionInfo
           #"Call to clojure.core/fn did not conform to spec"
           (eval '(fn))))))
+
+; this case is unreachable via Compiler.java since only up to 20 fixed arguments
+; are allowed. tests a bug in the invoke() method for RestFn with 21 arguments.
+(deftest restfn-arity-exception-test
+  ;; example 30 param function given 25 args
+  (is (thrown-with-msg? clojure.lang.ArityException
+                        #"Wrong number of args \(25\) passed to:.*"
+                        (apply (proxy [clojure.lang.RestFn] []
+                                 (getRequiredArity [] 30))
+                               (range 25))))
+  ;; test 21-30 args
+  (let [f (proxy [clojure.lang.RestFn] []
+            (getRequiredArity [] 30))]
+    (doseq [i (range 22 31)
+            :let [re (re-pattern (format "Wrong number of args \\(%s\\) passed to:.*" i))]]
+      (testing (pr-str re)
+        (is (thrown-with-msg? clojure.lang.ArityException
+                              re
+                              (apply f (range i))))))))