diff --git a/.github/ISSUE_TEMPLATE/jnigen.md b/.github/ISSUE_TEMPLATE/jnigen.md
index 0aacba402c..de9128814c 100644
--- a/.github/ISSUE_TEMPLATE/jnigen.md
+++ b/.github/ISSUE_TEMPLATE/jnigen.md
@@ -2,4 +2,5 @@
 name: "package:jnigen"
 about: "Create a bug or file a feature request against package:jnigen or its support library package:jni."
 labels: ["package:jnigen", "package:jni"]
+projects: ["dart-lang/69"]
 ---
diff --git a/pkgs/ffigen/README.md b/pkgs/ffigen/README.md
index 4323f559ad..6a62a64086 100644
--- a/pkgs/ffigen/README.md
+++ b/pkgs/ffigen/README.md
@@ -78,7 +78,6 @@ Jump to [FAQ](#faq).
 #### MacOS
 1. Install Xcode.
 2. Install Xcode command line tools - `xcode-select --install`.
-3. Install LLVM - `brew install llvm`.
 
 ## Configurations
 Configurations can be provided in 2 ways-
diff --git a/pkgs/jni/src/dartjni.c b/pkgs/jni/src/dartjni.c
index 5b2ac0c30e..0c2bff26e3 100644
--- a/pkgs/jni/src/dartjni.c
+++ b/pkgs/jni/src/dartjni.c
@@ -521,6 +521,8 @@ JniExceptionDetails getExceptionDetails(jthrowable exception) {
   JniExceptionDetails details;
   details.message = (*jniEnv)->CallObjectMethod(
       jniEnv, exception, exceptionMethods.toStringMethod);
+  // No exception is thrown from toString.
+  (*jniEnv)->ExceptionClear(jniEnv);
   jobject buffer =
       (*jniEnv)->NewObject(jniEnv, exceptionMethods.byteArrayOutputStreamClass,
                            exceptionMethods.byteArrayOutputStreamCtor);
@@ -529,8 +531,12 @@ JniExceptionDetails getExceptionDetails(jthrowable exception) {
                            exceptionMethods.printStreamCtor, buffer);
   (*jniEnv)->CallVoidMethod(
       jniEnv, exception, exceptionMethods.printStackTraceMethod, printStream);
+  // No exception is thrown from printStackTrace.
+  (*jniEnv)->ExceptionClear(jniEnv);
   details.stacktrace = (*jniEnv)->CallObjectMethod(
       jniEnv, buffer, exceptionMethods.toStringMethod);
+  // No exception is thrown from toString.
+  (*jniEnv)->ExceptionClear(jniEnv);
   details.message = to_global_ref(details.message);
   details.stacktrace = to_global_ref(details.stacktrace);
   return details;
diff --git a/pkgs/jni/test/boxed_test.dart b/pkgs/jni/test/boxed_test.dart
index 261b1acccd..d61938df6a 100644
--- a/pkgs/jni/test/boxed_test.dart
+++ b/pkgs/jni/test/boxed_test.dart
@@ -13,7 +13,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/exception_test.dart b/pkgs/jni/test/exception_test.dart
index 0c45ac8a66..bc2b89183f 100644
--- a/pkgs/jni/test/exception_test.dart
+++ b/pkgs/jni/test/exception_test.dart
@@ -20,8 +20,7 @@ void main() {
       Jni.spawn(dylibDir: "wrong_dir");
     } on HelperNotFoundError catch (_) {
       // stderr.write("\n$_\n");
-      Jni.spawnIfNotExists(
-          dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+      spawnJvm();
       caught = true;
     } on JniVmExistsError {
       stderr.writeln('cannot verify: HelperNotFoundError thrown');
diff --git a/pkgs/jni/test/global_env_test.dart b/pkgs/jni/test/global_env_test.dart
index 315225002d..4f40eaec0c 100644
--- a/pkgs/jni/test/global_env_test.dart
+++ b/pkgs/jni/test/global_env_test.dart
@@ -26,7 +26,7 @@ void main() {
 
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/isolate_test.dart b/pkgs/jni/test/isolate_test.dart
index 9b54f02ee1..a88d98c05c 100644
--- a/pkgs/jni/test/isolate_test.dart
+++ b/pkgs/jni/test/isolate_test.dart
@@ -14,7 +14,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jarray_test.dart b/pkgs/jni/test/jarray_test.dart
index c445e86cc0..fd4d119068 100644
--- a/pkgs/jni/test/jarray_test.dart
+++ b/pkgs/jni/test/jarray_test.dart
@@ -13,7 +13,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jbyte_buffer_test.dart b/pkgs/jni/test/jbyte_buffer_test.dart
index 2d4de825a0..fae8a6d5b7 100644
--- a/pkgs/jni/test/jbyte_buffer_test.dart
+++ b/pkgs/jni/test/jbyte_buffer_test.dart
@@ -14,7 +14,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jlist_test.dart b/pkgs/jni/test/jlist_test.dart
index b410525be9..329d9c249e 100644
--- a/pkgs/jni/test/jlist_test.dart
+++ b/pkgs/jni/test/jlist_test.dart
@@ -13,7 +13,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jmap_test.dart b/pkgs/jni/test/jmap_test.dart
index 4ece7517f1..0c157567b5 100644
--- a/pkgs/jni/test/jmap_test.dart
+++ b/pkgs/jni/test/jmap_test.dart
@@ -12,7 +12,7 @@ import 'test_util/test_util.dart';
 void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jobject_test.dart b/pkgs/jni/test/jobject_test.dart
index 1f1c419644..362e182432 100644
--- a/pkgs/jni/test/jobject_test.dart
+++ b/pkgs/jni/test/jobject_test.dart
@@ -17,7 +17,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jset_test.dart b/pkgs/jni/test/jset_test.dart
index 2d93e6334d..cfe8a71586 100644
--- a/pkgs/jni/test/jset_test.dart
+++ b/pkgs/jni/test/jset_test.dart
@@ -13,7 +13,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/jstring_test.dart b/pkgs/jni/test/jstring_test.dart
index c1a968c465..a699e30905 100644
--- a/pkgs/jni/test/jstring_test.dart
+++ b/pkgs/jni/test/jstring_test.dart
@@ -13,7 +13,7 @@ void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/load_test.dart b/pkgs/jni/test/load_test.dart
index 78e1511776..27cc6ad71f 100644
--- a/pkgs/jni/test/load_test.dart
+++ b/pkgs/jni/test/load_test.dart
@@ -32,7 +32,7 @@ void doGC() {
 void main() {
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jni/test/test_util/test_util.dart b/pkgs/jni/test/test_util/test_util.dart
index fcdafad2c1..841705f00c 100644
--- a/pkgs/jni/test/test_util/test_util.dart
+++ b/pkgs/jni/test/test_util/test_util.dart
@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:jni/jni.dart';
 import 'package:jni/src/build_util/build_util.dart';
 
 typedef TestCaseCallback = void Function();
@@ -34,3 +35,8 @@ void checkDylibIsUpToDate() {
     exit(1);
   }
 }
+
+void spawnJvm() {
+  Jni.spawnIfNotExists(
+      dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m", "-Xcheck:jni"]);
+}
diff --git a/pkgs/jni/test/type_test.dart b/pkgs/jni/test/type_test.dart
index 2962b09e92..f00c471034 100644
--- a/pkgs/jni/test/type_test.dart
+++ b/pkgs/jni/test/type_test.dart
@@ -205,7 +205,7 @@ final class $FType extends JObjType<F> {
 void main() {
   if (!Platform.isAndroid) {
     checkDylibIsUpToDate();
-    Jni.spawnIfNotExists(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
+    spawnJvm();
   }
   run(testRunner: test);
 }
diff --git a/pkgs/jnigen/test/test_util/bindings_test_setup.dart b/pkgs/jnigen/test/test_util/bindings_test_setup.dart
index 0c9d723d2f..2800aa1e74 100644
--- a/pkgs/jnigen/test/test_util/bindings_test_setup.dart
+++ b/pkgs/jnigen/test/test_util/bindings_test_setup.dart
@@ -67,6 +67,8 @@ Future<void> bindingsTestSetup() async {
       tempClassDir.path,
       ...jacksonJars,
       kotlinTestJar,
+    ], jvmOptions: [
+      "-Xcheck:jni",
     ]);
   }
 }