diff --git a/.github/workflows/maven-build.yml b/.github/workflows/maven-build.yml
index fa07eabc3..8a2b59f8d 100644
--- a/.github/workflows/maven-build.yml
+++ b/.github/workflows/maven-build.yml
@@ -2,14 +2,18 @@ name: CI
 
 on: [push, pull_request]
 
+# this is required by spotless for JDK 16+
+env:
+  JAVA_11_PLUS_MAVEN_OPTS: "--add-opens jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED --add-opens jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED"
 
 jobs:
   build:
     name: build-only (Java ${{ matrix.java }})
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
-        java: [ 13 ]
+        java: [ 16 ]
     steps:
       - uses: actions/checkout@v2
       - name: Set up JDK
@@ -24,11 +28,14 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-maven-
       - name: Maven Install (skipTests)
+        env:
+          MAVEN_OPTS: ${{ env.JAVA_11_PLUS_MAVEN_OPTS }}
         run: mvn -B install -DskipTests -D enable-ci --file pom.xml
   site:
     name: site (Java ${{ matrix.java }})
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         java: [ 8, 11 ]
     steps:
@@ -49,9 +56,10 @@ jobs:
     name: test (${{ matrix.os }}, Java ${{ matrix.java }})
     runs-on: ${{ matrix.os }}-latest
     strategy:
+      fail-fast: false
       matrix:
         os: [ ubuntu, windows ]
-        java: [ 8, 11, 13, 15-ea ]
+        java: [ 8, 11, 16 ]
     steps:
     - uses: actions/checkout@v2
     - name: Set up JDK
@@ -64,9 +72,21 @@ jobs:
         key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
         restore-keys: |
           ${{ runner.os }}-maven-
+    # JDK 8
     - name: Maven Install without Code Coverage
-      if: matrix.os == 'windows'
+      if: matrix.os == 'windows' && matrix.java == '8'
       run: mvn -B install --file pom.xml
     - name: Maven Install with Code Coverage
-      if: matrix.os != 'windows'
+      if: matrix.os != 'windows' && matrix.java == '8'
+      run: mvn -B install -D enable-ci --file pom.xml
+    # JDK 11+
+    - name: Maven Install without Code Coverage
+      if: matrix.os == 'windows' && matrix.java != '8'
+      env:
+        MAVEN_OPTS: ${{ env.JAVA_11_PLUS_MAVEN_OPTS }}
+      run: mvn -B install --file pom.xml
+    - name: Maven Install with Code Coverage
+      if: matrix.os != 'windows' && matrix.java != '8'
+      env:
+        MAVEN_OPTS: ${{ env.JAVA_11_PLUS_MAVEN_OPTS }}
       run: mvn -B install -D enable-ci --file pom.xml
diff --git a/pom.xml b/pom.xml
index e18e28a7f..cef2825ce 100644
--- a/pom.xml
+++ b/pom.xml
@@ -45,6 +45,8 @@
     <!-- For non-ci builds we'd like the build to still complete if jacoco metrics aren't met. -->
     <jacoco.haltOnFailure>false</jacoco.haltOnFailure>
     <jjwt.suite.version>0.11.2</jjwt.suite.version>
+
+    <surefire.argLine></surefire.argLine>
   </properties>
 
   <build>
@@ -272,6 +274,7 @@
             <id>default-test</id>
             <configuration>
               <excludesFile>src/test/resources/slow-or-flaky-tests.txt</excludesFile>
+              <argLine>${surefire.argLine}</argLine>
             </configuration>
           </execution>
           <execution>
@@ -284,6 +287,7 @@
               <rerunFailingTestsCount>2</rerunFailingTestsCount>
               <!-- There are some tests that take longer or are a little flaky.  Run them here. -->
               <includesFile>src/test/resources/slow-or-flaky-tests.txt</includesFile>
+              <argLine>${surefire.argLine}</argLine>
             </configuration>
           </execution>
         </executions>
@@ -561,6 +565,16 @@
     </pluginRepository>
   </pluginRepositories>
   <profiles>
+    <profile>
+      <id>jdk11+</id>
+      <activation>
+        <jdk>[11,)</jdk>
+      </activation>
+      <properties>
+        <!-- this is required for GithubHttpUrlConnectionClient#setRequestMethod() to work with JDK 16+ -->
+        <surefire.argLine>--add-opens java.base/java.net=ALL-UNNAMED</surefire.argLine>
+      </properties>
+    </profile>
     <profile>
       <id>ci-non-windows</id>
       <activation>
diff --git a/src/test/java/org/kohsuke/github/GitHubConnectionTest.java b/src/test/java/org/kohsuke/github/GitHubConnectionTest.java
index 0fb168eae..98be781fa 100644
--- a/src/test/java/org/kohsuke/github/GitHubConnectionTest.java
+++ b/src/test/java/org/kohsuke/github/GitHubConnectionTest.java
@@ -1,13 +1,20 @@
 package org.kohsuke.github;
 
+import org.junit.Assume;
 import org.junit.Test;
 import org.kohsuke.github.authorization.UserAuthorizationProvider;
 
 import java.io.IOException;
 import java.lang.reflect.Field;
-import java.util.*;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
-import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.lessThan;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
 
 /**
  * Unit test for {@link GitHub}.
@@ -56,6 +63,8 @@ public class GitHubConnectionTest extends AbstractGitHubWireMockTest {
 
     @Test
     public void testGitHubBuilderFromEnvironment() throws IOException {
+        // we disable this test for JDK 16+ as the current hacks in setupEnvironment() don't work with JDK 16+
+        Assume.assumeThat(Double.valueOf(System.getProperty("java.specification.version")), lessThan(16.0));
 
         Map<String, String> props = new HashMap<String, String>();
 
@@ -98,6 +107,9 @@ public class GitHubConnectionTest extends AbstractGitHubWireMockTest {
 
     @Test
     public void testGitHubBuilderFromCustomEnvironment() throws IOException {
+        // we disable this test for JDK 16+ as the current hacks in setupEnvironment() don't work with JDK 16+
+        Assume.assumeThat(Double.valueOf(System.getProperty("java.specification.version")), lessThan(16.0));
+
         Map<String, String> props = new HashMap<String, String>();
 
         props.put("customEndpoint", "bogus endpoint url");