diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ae58a1ae..c1402b10 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -8,11 +8,15 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java-version: [ 8, 11, 17, 20 ]
+        java-version: [ 8, 11, 17, 21 ]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
         with:
           distribution: 'temurin'
-          java-version: ${{ matrix.java-version }}
-      - run: ./gradlew assemble check --info
\ No newline at end of file
+          java-version: |
+            ${{ matrix.java-version }}
+            21
+      - run: ./gradlew assemble check --info
+        env:
+          JAVA_TOOLCHAIN: ${{ matrix.java-version }}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index ce4b945a..7eb48332 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,10 +3,18 @@ plugins {
     id 'scala'
     id 'signing'
     id 'maven-publish'
-    // pinned version due to Java 8 compatibility
-    id "com.diffplug.spotless" version "6.11.0"
-    // pinned version due to https://github.com/spotbugs/spotbugs/issues/2041
-    id "com.github.spotbugs" version "5.0.13"
+    id "com.diffplug.spotless" version "6.22.0"
+    id "com.github.spotbugs" version "5.2.1"
+}
+
+var javaToolchain = System.getenv('JAVA_TOOLCHAIN')
+
+java {
+    if (javaToolchain != null) {
+        toolchain {
+            languageVersion = JavaLanguageVersion.of(javaToolchain)
+        }
+    }
 }
 
 compileJava {
@@ -39,7 +47,8 @@ dependencies {
 
 spotless {
     java {
-        palantirJavaFormat()
+         // remove when spotless moved to this Palantir version
+         palantirJavaFormat("2.38.0")
     }
     scala {
         scalafmt('3.7.1').configFile('.scalafmt.conf')
@@ -48,10 +57,10 @@ spotless {
 
 // There are some compatibility issues with spotless older Java versions,
 // but we don't need to cross-do style checks anyway
-if (JavaVersion.current().ordinal() < JavaVersion.VERSION_17.ordinal()) {
-    tasks.findByName("spotlessScala").enabled(false)
-    tasks.findByName("spotlessJava").enabled(false)
-}
+// if (JavaVersion.current().ordinal() < JavaVersion.VERSION_17.ordinal()) {
+//     tasks.findByName("spotlessScala").enabled(false)
+//     tasks.findByName("spotlessJava").enabled(false)
+// }
 
 spotbugs {
     ignoreFailures = false
diff --git a/src/test/scala/tlschannel/TestLogger.java b/src/test/scala/tlschannel/TestLogger.java
new file mode 100644
index 00000000..e6723fb0
--- /dev/null
+++ b/src/test/scala/tlschannel/TestLogger.java
@@ -0,0 +1,14 @@
+package tlschannel;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+
+@TestInstance(Lifecycle.PER_CLASS)
+public class TestLogger {
+
+    @Test
+    public void logJdk() {
+        System.out.println("java.version: " + System.getProperty("java.version"));
+    }
+}