diff --git a/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodAndroidApiTest.java b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodAndroidApiTest.java
new file mode 100644
index 0000000..c11c1bb
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodAndroidApiTest.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.platform.test.ravenwood.bivalenttest;
+
+import static org.junit.Assert.assertEquals;
+
+import android.util.ArrayMap;
+import android.util.Size;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.Map;
+
+// Tests for calling simple Android APIs.
+@RunWith(AndroidJUnit4.class)
+public class RavenwoodAndroidApiTest {
+    @Test
+    public void testArrayMapSimple() {
+        final Map<String, String> map = new ArrayMap<>();
+
+        map.put("key1", "value1");
+        assertEquals("value1", map.get("key1"));
+    }
+
+    @Test
+    public void testSizeSimple() {
+        final var size = new Size(1, 2);
+
+        assertEquals(2, size.getHeight());
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleDeviceOnlyTest.java b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleDeviceOnlyTest.java
new file mode 100644
index 0000000..6f2465c
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleDeviceOnlyTest.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.platform.test.ravenwood.bivalenttest;
+
+import android.platform.test.annotations.DisabledOnRavenwood;
+import android.platform.test.ravenwood.RavenwoodClassRule;
+import android.platform.test.ravenwood.RavenwoodRule;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Assert;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@DisabledOnRavenwood
+public class RavenwoodClassRuleDeviceOnlyTest {
+    @ClassRule
+    public static final RavenwoodClassRule sRavenwood = new RavenwoodClassRule();
+
+    @Test
+    public void testDeviceOnly() {
+        Assert.assertFalse(RavenwoodRule.isOnRavenwood());
+    }
+}
diff --git a/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleRavenwoodOnlyTest.java b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleRavenwoodOnlyTest.java
new file mode 100644
index 0000000..21b31d1
--- /dev/null
+++ b/ravenwood/bivalenttest/test/com/android/platform/test/ravenwood/bivalenttest/RavenwoodClassRuleRavenwoodOnlyTest.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.platform.test.ravenwood.bivalenttest;
+
+import android.platform.test.ravenwood.RavenwoodClassRule;
+import android.platform.test.ravenwood.RavenwoodRule;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Assert;
+import org.junit.ClassRule;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+// TODO: atest RavenwoodBivalentTest_device fails with the following message.
+// `RUNNER ERROR: Instrumentation reported numtests=7 but only ran 6`
+// @android.platform.test.annotations.DisabledOnNonRavenwood
+// Figure it out and then make DisabledOnNonRavenwood support TYPEs as well.
+@Ignore
+public class RavenwoodClassRuleRavenwoodOnlyTest {
+    @ClassRule
+    public static final RavenwoodClassRule sRavenwood = new RavenwoodClassRule();
+
+    @Test
+    public void testRavenwoodOnly() {
+        Assert.assertTrue(RavenwoodRule.isOnRavenwood());
+    }
+}
diff --git a/ravenwood/coretest/test/com/android/platform/test/ravenwood/coretest/RavenwoodTestRunnerValidationTest.java b/ravenwood/coretest/test/com/android/platform/test/ravenwood/coretest/RavenwoodTestRunnerValidationTest.java
index 2cd585f..4ee9a9c 100644
--- a/ravenwood/coretest/test/com/android/platform/test/ravenwood/coretest/RavenwoodTestRunnerValidationTest.java
+++ b/ravenwood/coretest/test/com/android/platform/test/ravenwood/coretest/RavenwoodTestRunnerValidationTest.java
@@ -40,7 +40,7 @@
     public final RuleChain chain = RuleChain.outerRule(mThrown).around(mRavenwood);
 
     public RavenwoodTestRunnerValidationTest() {
-        Assume.assumeTrue(mRavenwood._ravenwood_private$isOptionalValidationEnabled());
+        Assume.assumeTrue(RavenwoodRule._$RavenwoodPrivate.isOptionalValidationEnabled());
         // Because RavenwoodRule will throw this error before executing the test method,
         // we can't do it in the test method itself.
         // So instead, we initialize it here.
diff --git a/ravenwood/junit-src/android/platform/test/annotations/DisabledOnNonRavenwood.java b/ravenwood/junit-src/android/platform/test/annotations/DisabledOnNonRavenwood.java
index 8ca34ba..9d47f3a 100644
--- a/ravenwood/junit-src/android/platform/test/annotations/DisabledOnNonRavenwood.java
+++ b/ravenwood/junit-src/android/platform/test/annotations/DisabledOnNonRavenwood.java
@@ -31,13 +31,17 @@
  * which means if a test class has this annotation, you can't negate it in subclasses or
  * on a per-method basis.
  *
+ * THIS ANNOTATION CANNOT BE ADDED TO CLASSES AT THIS PONINT.
+ * See {@link com.android.platform.test.ravenwood.bivalenttest.RavenwoodClassRuleRavenwoodOnlyTest}
+ * for the reason.
+ *
  * The {@code RAVENWOOD_RUN_DISABLED_TESTS} environmental variable won't work because it won't be
  * propagated to the device. (We may support it in the future, possibly using a debug. sysprop.)
  *
  * @hide
  */
 @Inherited
-@Target({ElementType.METHOD, ElementType.TYPE})
+@Target({ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 public @interface DisabledOnNonRavenwood {
     /**
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodClassRule.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodClassRule.java
index 9a4d488..f4b7ec36 100644
--- a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodClassRule.java
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodClassRule.java
@@ -25,6 +25,7 @@
 import android.platform.test.annotations.DisabledOnRavenwood;
 import android.platform.test.annotations.EnabledOnRavenwood;
 
+import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.rules.TestRule;
 import org.junit.runner.Description;
@@ -41,27 +42,16 @@
 public class RavenwoodClassRule implements TestRule {
     @Override
     public Statement apply(Statement base, Description description) {
-        // No special treatment when running outside Ravenwood; run tests as-is
         if (!IS_ON_RAVENWOOD) {
-            Assume.assumeTrue(shouldEnableOnDevice(description));
-            return base;
-        }
-
-        if (ENABLE_PROBE_IGNORED) {
+            // This should be "Assume", not Assert, but if we use assume here, the device side
+            // test runner would complain.
+            // See the TODO comment in RavenwoodClassRuleRavenwoodOnlyTest.
+            Assert.assertTrue(shouldEnableOnDevice(description));
+        } else if (ENABLE_PROBE_IGNORED) {
             Assume.assumeFalse(shouldStillIgnoreInProbeIgnoreMode(description));
-            // Pass through to possible underlying RavenwoodRule for both environment
-            // configuration and handling method-level annotations
-            return base;
         } else {
-            return new Statement() {
-                @Override
-                public void evaluate() throws Throwable {
-                    Assume.assumeTrue(shouldEnableOnRavenwood(description));
-                    // Pass through to possible underlying RavenwoodRule for both environment
-                    // configuration and handling method-level annotations
-                    base.evaluate();
-                }
-            };
+            Assume.assumeTrue(shouldEnableOnRavenwood(description));
         }
+        return base;
     }
 }
diff --git a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
index 52ea340..a2e8ec1 100644
--- a/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
+++ b/ravenwood/junit-src/android/platform/test/ravenwood/RavenwoodRule.java
@@ -28,7 +28,6 @@
 import android.platform.test.annotations.DisabledOnRavenwood;
 import android.platform.test.annotations.EnabledOnRavenwood;
 import android.platform.test.annotations.IgnoreUnderRavenwood;
-import android.util.ArraySet;
 
 import org.junit.Assume;
 import org.junit.rules.TestRule;
@@ -278,6 +277,9 @@
                 return false;
             }
         }
+        if (description.getTestClass().getAnnotation(DisabledOnNonRavenwood.class) != null) {
+            return false;
+        }
         return true;
     }
 
@@ -413,10 +415,9 @@
         };
     }
 
-    /**
-     * Do not use it outside ravenwood core classes.
-     */
-    public boolean _ravenwood_private$isOptionalValidationEnabled() {
-        return ENABLE_OPTIONAL_VALIDATION;
+    public static class _$RavenwoodPrivate {
+        public static boolean isOptionalValidationEnabled() {
+            return ENABLE_OPTIONAL_VALIDATION;
+        }
     }
 }
diff --git a/tools/hoststubgen/hoststubgen/Android.bp b/tools/hoststubgen/hoststubgen/Android.bp
index 30333da..682adbc 100644
--- a/tools/hoststubgen/hoststubgen/Android.bp
+++ b/tools/hoststubgen/hoststubgen/Android.bp
@@ -82,13 +82,30 @@
     jarjar_rules: "jarjar-rules.txt",
 }
 
-// Host-side stub generator tool.
-java_binary_host {
-    name: "hoststubgen",
-    main_class: "com.android.hoststubgen.Main",
+// For sharing the code with other tools
+java_library_host {
+    name: "hoststubgen-lib",
+    defaults: ["ravenwood-internal-only-visibility-java"],
     srcs: ["src/**/*.kt"],
     static_libs: [
         "hoststubgen-helper-runtime",
+    ],
+    libs: [
+        "junit",
+        "ow2-asm",
+        "ow2-asm-analysis",
+        "ow2-asm-commons",
+        "ow2-asm-tree",
+        "ow2-asm-util",
+    ],
+}
+
+// Host-side stub generator tool.
+java_binary_host {
+    name: "hoststubgen",
+    main_class: "com.android.hoststubgen.HostStubGenMain",
+    static_libs: [
+        "hoststubgen-lib",
         "junit",
         "ow2-asm",
         "ow2-asm-analysis",
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
index 1089f82..803dc28 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
@@ -32,7 +32,6 @@
 import org.objectweb.asm.ClassReader
 import org.objectweb.asm.ClassVisitor
 import org.objectweb.asm.ClassWriter
-import org.objectweb.asm.tree.ClassNode
 import org.objectweb.asm.util.CheckClassAdapter
 import java.io.BufferedInputStream
 import java.io.FileOutputStream
@@ -52,7 +51,7 @@
         val stats = HostStubGenStats()
 
         // Load all classes.
-        val allClasses = loadClassStructures(options.inJar.get)
+        val allClasses = ClassNodes.loadClassStructures(options.inJar.get)
 
         // Dump the classes, if specified.
         options.inputJarDumpFile.ifSet {
@@ -92,55 +91,6 @@
     }
 
     /**
-     * Load all the classes, without code.
-     */
-    private fun loadClassStructures(inJar: String): ClassNodes {
-        log.i("Reading class structure from $inJar ...")
-        val start = System.currentTimeMillis()
-
-        val allClasses = ClassNodes()
-
-        log.withIndent {
-            ZipFile(inJar).use { inZip ->
-                val inEntries = inZip.entries()
-
-                while (inEntries.hasMoreElements()) {
-                    val entry = inEntries.nextElement()
-
-                    BufferedInputStream(inZip.getInputStream(entry)).use { bis ->
-                        if (entry.name.endsWith(".class")) {
-                            val cr = ClassReader(bis)
-                            val cn = ClassNode()
-                            cr.accept(cn, ClassReader.SKIP_CODE or ClassReader.SKIP_DEBUG
-                                    or ClassReader.SKIP_FRAMES)
-                            if (!allClasses.addClass(cn)) {
-                                log.w("Duplicate class found: ${cn.name}")
-                            }
-                        } else if (entry.name.endsWith(".dex")) {
-                            // Seems like it's an ART jar file. We can't process it.
-                            // It's a fatal error.
-                            throw InvalidJarFileException(
-                                    "$inJar is not a desktop jar file. It contains a *.dex file.")
-                        } else {
-                            // Unknown file type. Skip.
-                            while (bis.available() > 0) {
-                                bis.skip((1024 * 1024).toLong())
-                            }
-                        }
-                    }
-                }
-            }
-        }
-        if (allClasses.size == 0) {
-            log.w("$inJar contains no *.class files.")
-        }
-
-        val end = System.currentTimeMillis()
-        log.i("Done reading class structure in %.1f second(s).", (end - start) / 1000.0)
-        return allClasses
-    }
-
-    /**
      * Build the filter, which decides what classes/methods/fields should be put in stub or impl
      * jars, and "how". (e.g. with substitution?)
      */
@@ -229,7 +179,7 @@
         val intersectingJars = mutableMapOf<String, ClassNodes>()
 
         filenames.forEach { filename ->
-            intersectingJars[filename] = loadClassStructures(filename)
+            intersectingJars[filename] = ClassNodes.loadClassStructures(filename)
         }
         return intersectingJars
     }
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Main.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenMain.kt
similarity index 86%
rename from tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Main.kt
rename to tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenMain.kt
index 4882c00..45e7e30 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Main.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenMain.kt
@@ -13,18 +13,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-@file:JvmName("Main")
+@file:JvmName("HostStubGenMain")
 
 package com.android.hoststubgen
 
 import java.io.PrintWriter
 
-const val COMMAND_NAME = "HostStubGen"
-
 /**
  * Entry point.
  */
 fun main(args: Array<String>) {
+    executableName = "HostStubGen"
+
     var success = false
     var clanupOnError = false
 
@@ -33,7 +33,7 @@
         val options = HostStubGenOptions.parseArgs(args)
         clanupOnError = options.cleanUpOnError.get
 
-        log.v("HostStubGen started")
+        log.v("$executableName started")
         log.v("Options: $options")
 
         // Run.
@@ -41,7 +41,7 @@
 
         success = true
     } catch (e: Throwable) {
-        log.e("$COMMAND_NAME: Error: ${e.message}")
+        log.e("$executableName: Error: ${e.message}")
         if (e !is UserErrorException) {
             e.printStackTrace(PrintWriter(log.getWriter(LogLevel.Error)))
         }
@@ -49,7 +49,7 @@
             TODO("Remove output jars here")
         }
     } finally {
-        log.i("$COMMAND_NAME finished")
+        log.i("$executableName finished")
         log.flush()
     }
 
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
index 9f5d524..9ff798a 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
@@ -268,7 +268,7 @@
             }
             if (!ret.outStubJar.isSet && !ret.outImplJar.isSet) {
                 log.w("Neither --out-stub-jar nor --out-impl-jar is set." +
-                        " $COMMAND_NAME will not generate jar files.")
+                        " $executableName will not generate jar files.")
             }
 
             if (ret.enableNonStubMethodCallDetection.get) {
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Utils.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Utils.kt
index 937e56c..aa63d8d9 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Utils.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/Utils.kt
@@ -16,6 +16,11 @@
 package com.android.hoststubgen
 
 /**
+ * Name of this executable. Set it in the main method.
+ */
+var executableName = "[command name not set]"
+
+/**
  * A regex that maches whitespate.
  */
 val whitespaceRegex = """\s+""".toRegex()
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/AsmUtils.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/AsmUtils.kt
index 0579c2b..83e122f 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/AsmUtils.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/AsmUtils.kt
@@ -34,6 +34,9 @@
 /** Descriptor of the class initializer method. */
 val CLASS_INITIALIZER_DESC = "()V"
 
+/** Name of constructors. */
+val CTOR_NAME = "<init>"
+
 /**
  * Find any of [anyAnnotations] from the list of visible / invisible annotations.
  */
@@ -135,10 +138,10 @@
         // Note, long and double will consume two local variable spaces, so the extra `i++`.
         when (type) {
             Type.VOID_TYPE -> throw HostStubGenInternalException("VOID_TYPE not expected")
-            Type.BOOLEAN_TYPE, Type.INT_TYPE, Type.SHORT_TYPE, Type.CHAR_TYPE
+            Type.BOOLEAN_TYPE, Type.CHAR_TYPE, Type.BYTE_TYPE, Type.SHORT_TYPE, Type.INT_TYPE
                 -> writer.visitVarInsn(Opcodes.ILOAD, i)
-            Type.LONG_TYPE -> writer.visitVarInsn(Opcodes.LLOAD, i++)
             Type.FLOAT_TYPE -> writer.visitVarInsn(Opcodes.FLOAD, i)
+            Type.LONG_TYPE -> writer.visitVarInsn(Opcodes.LLOAD, i++)
             Type.DOUBLE_TYPE -> writer.visitVarInsn(Opcodes.DLOAD, i++)
             else -> writer.visitVarInsn(Opcodes.ALOAD, i)
         }
@@ -154,10 +157,10 @@
         // See https://en.wikipedia.org/wiki/List_of_Java_bytecode_instructions
         when (type) {
             Type.VOID_TYPE -> writer.visitInsn(Opcodes.RETURN)
-            Type.BOOLEAN_TYPE, Type.INT_TYPE, Type.SHORT_TYPE, Type.CHAR_TYPE
+            Type.BOOLEAN_TYPE, Type.CHAR_TYPE, Type.BYTE_TYPE, Type.SHORT_TYPE, Type.INT_TYPE
                 -> writer.visitInsn(Opcodes.IRETURN)
-            Type.LONG_TYPE -> writer.visitInsn(Opcodes.LRETURN)
             Type.FLOAT_TYPE -> writer.visitInsn(Opcodes.FRETURN)
+            Type.LONG_TYPE -> writer.visitInsn(Opcodes.LRETURN)
             Type.DOUBLE_TYPE -> writer.visitInsn(Opcodes.DRETURN)
             else -> writer.visitInsn(Opcodes.ARETURN)
         }
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/ClassNodes.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/ClassNodes.kt
index bc34ef0..92906a7 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/ClassNodes.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/asm/ClassNodes.kt
@@ -16,13 +16,18 @@
 package com.android.hoststubgen.asm
 
 import com.android.hoststubgen.ClassParseException
+import com.android.hoststubgen.InvalidJarFileException
+import com.android.hoststubgen.log
+import org.objectweb.asm.ClassReader
 import org.objectweb.asm.tree.AnnotationNode
 import org.objectweb.asm.tree.ClassNode
 import org.objectweb.asm.tree.FieldNode
 import org.objectweb.asm.tree.MethodNode
 import org.objectweb.asm.tree.TypeAnnotationNode
+import java.io.BufferedInputStream
 import java.io.PrintWriter
 import java.util.Arrays
+import java.util.zip.ZipFile
 
 /**
  * Stores all classes loaded from a jar file, in a form of [ClassNode]
@@ -62,8 +67,8 @@
 
     /** Find a field, which may not exist. */
     fun findField(
-            className: String,
-            fieldName: String,
+        className: String,
+        fieldName: String,
     ): FieldNode? {
         return findClass(className)?.fields?.firstOrNull { it.name == fieldName }?.let { fn ->
             return fn
@@ -72,14 +77,14 @@
 
     /** Find a method, which may not exist. */
     fun findMethod(
-            className: String,
-            methodName: String,
-            descriptor: String,
+        className: String,
+        methodName: String,
+        descriptor: String,
     ): MethodNode? {
         return findClass(className)?.methods
-                ?.firstOrNull { it.name == methodName && it.desc == descriptor }?.let { mn ->
-            return mn
-        }
+            ?.firstOrNull { it.name == methodName && it.desc == descriptor }?.let { mn ->
+                return mn
+            }
     }
 
     /** @return true if a class has a class initializer. */
@@ -106,26 +111,33 @@
 
     private fun dumpClass(pw: PrintWriter, cn: ClassNode) {
         pw.printf("Class: %s [access: %x]\n", cn.name, cn.access)
-        dumpAnnotations(pw, "  ",
-                cn.visibleTypeAnnotations, cn.invisibleTypeAnnotations,
-                cn.visibleAnnotations, cn.invisibleAnnotations,
-                )
+        dumpAnnotations(
+            pw, "  ",
+            cn.visibleTypeAnnotations, cn.invisibleTypeAnnotations,
+            cn.visibleAnnotations, cn.invisibleAnnotations,
+        )
 
         for (f in cn.fields ?: emptyList()) {
-            pw.printf("  Field: %s [sig: %s] [desc: %s] [access: %x]\n",
-                    f.name, f.signature, f.desc, f.access)
-            dumpAnnotations(pw, "    ",
-                    f.visibleTypeAnnotations, f.invisibleTypeAnnotations,
-                    f.visibleAnnotations, f.invisibleAnnotations,
-                    )
+            pw.printf(
+                "  Field: %s [sig: %s] [desc: %s] [access: %x]\n",
+                f.name, f.signature, f.desc, f.access
+            )
+            dumpAnnotations(
+                pw, "    ",
+                f.visibleTypeAnnotations, f.invisibleTypeAnnotations,
+                f.visibleAnnotations, f.invisibleAnnotations,
+            )
         }
         for (m in cn.methods ?: emptyList()) {
-            pw.printf("  Method: %s [sig: %s] [desc: %s] [access: %x]\n",
-                    m.name, m.signature, m.desc, m.access)
-            dumpAnnotations(pw, "    ",
-                    m.visibleTypeAnnotations, m.invisibleTypeAnnotations,
-                    m.visibleAnnotations, m.invisibleAnnotations,
-                    )
+            pw.printf(
+                "  Method: %s [sig: %s] [desc: %s] [access: %x]\n",
+                m.name, m.signature, m.desc, m.access
+            )
+            dumpAnnotations(
+                pw, "    ",
+                m.visibleTypeAnnotations, m.invisibleTypeAnnotations,
+                m.visibleAnnotations, m.invisibleAnnotations,
+            )
         }
     }
 
@@ -136,7 +148,7 @@
         invisibleTypeAnnotations: List<TypeAnnotationNode>?,
         visibleAnnotations: List<AnnotationNode>?,
         invisibleAnnotations: List<AnnotationNode>?,
-        ) {
+    ) {
         for (an in visibleTypeAnnotations ?: emptyList()) {
             pw.printf("%sTypeAnnotation(vis): %s\n", prefix, an.desc)
         }
@@ -166,4 +178,55 @@
             }
         }
     }
+
+    companion object {
+        /**
+         * Load all the classes, without code.
+         */
+        fun loadClassStructures(inJar: String): ClassNodes {
+            log.i("Reading class structure from $inJar ...")
+            val start = System.currentTimeMillis()
+
+            val allClasses = ClassNodes()
+
+            log.withIndent {
+                ZipFile(inJar).use { inZip ->
+                    val inEntries = inZip.entries()
+
+                    while (inEntries.hasMoreElements()) {
+                        val entry = inEntries.nextElement()
+
+                        BufferedInputStream(inZip.getInputStream(entry)).use { bis ->
+                            if (entry.name.endsWith(".class")) {
+                                val cr = ClassReader(bis)
+                                val cn = ClassNode()
+                                cr.accept(cn, ClassReader.SKIP_CODE or ClassReader.SKIP_DEBUG
+                                        or ClassReader.SKIP_FRAMES)
+                                if (!allClasses.addClass(cn)) {
+                                    log.w("Duplicate class found: ${cn.name}")
+                                }
+                            } else if (entry.name.endsWith(".dex")) {
+                                // Seems like it's an ART jar file. We can't process it.
+                                // It's a fatal error.
+                                throw InvalidJarFileException(
+                                    "$inJar is not a desktop jar file. It contains a *.dex file.")
+                            } else {
+                                // Unknown file type. Skip.
+                                while (bis.available() > 0) {
+                                    bis.skip((1024 * 1024).toLong())
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            if (allClasses.size == 0) {
+                log.w("$inJar contains no *.class files.")
+            }
+
+            val end = System.currentTimeMillis()
+            log.i("Done reading class structure in %.1f second(s).", (end - start) / 1000.0)
+            return allClasses
+        }
+    }
 }
\ No newline at end of file
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/ImplicitOutputFilter.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/ImplicitOutputFilter.kt
index 78b13fd..5a26fc6 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/ImplicitOutputFilter.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/ImplicitOutputFilter.kt
@@ -19,14 +19,14 @@
 import com.android.hoststubgen.HostStubGenInternalException
 import com.android.hoststubgen.asm.CLASS_INITIALIZER_DESC
 import com.android.hoststubgen.asm.CLASS_INITIALIZER_NAME
-import com.android.hoststubgen.asm.isAnonymousInnerClass
-import com.android.hoststubgen.log
 import com.android.hoststubgen.asm.ClassNodes
 import com.android.hoststubgen.asm.isAnnotation
+import com.android.hoststubgen.asm.isAnonymousInnerClass
 import com.android.hoststubgen.asm.isAutoGeneratedEnumMember
 import com.android.hoststubgen.asm.isEnum
 import com.android.hoststubgen.asm.isSynthetic
 import com.android.hoststubgen.asm.isVisibilityPrivateOrPackagePrivate
+import com.android.hoststubgen.log
 import org.objectweb.asm.tree.ClassNode
 
 /**
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/01-hoststubgen-test-tiny-framework-orig-dump.txt b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/01-hoststubgen-test-tiny-framework-orig-dump.txt
index f70a17d..fa8fe6c 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/01-hoststubgen-test-tiny-framework-orig-dump.txt
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/01-hoststubgen-test-tiny-framework-orig-dump.txt
@@ -1833,7 +1833,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                         // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 1, methods: 10, attributes: 2
+  interfaces: 0, fields: 1, methods: 11, attributes: 2
   int value;
     descriptor: I
     flags: (0x0000)
@@ -1938,6 +1938,10 @@
          x: invokespecial #x                 // Method java/lang/RuntimeException."<init>":()V
          x: athrow
       LineNumberTable:
+
+  public static native byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
 }
 SourceFile: "TinyFrameworkNative.java"
 RuntimeInvisibleAnnotations:
@@ -1955,7 +1959,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                         // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 0, methods: 4, attributes: 2
+  interfaces: 0, fields: 0, methods: 5, attributes: 2
   public com.android.hoststubgen.test.tinyframework.TinyFrameworkNative_host();
     descriptor: ()V
     flags: (0x0001) ACC_PUBLIC
@@ -2013,6 +2017,22 @@
         Start  Length  Slot  Name   Signature
             0       7     0 source   Lcom/android/hoststubgen/test/tinyframework/TinyFrameworkNative;
             0       7     1   arg   I
+
+  public static byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=2, locals=2, args_size=2
+         x: iload_0
+         x: iload_1
+         x: iadd
+         x: i2b
+         x: ireturn
+      LineNumberTable:
+      LocalVariableTable:
+        Start  Length  Slot  Name   Signature
+            0       5     0  arg1   B
+            0       5     1  arg2   B
 }
 SourceFile: "TinyFrameworkNative_host.java"
 RuntimeInvisibleAnnotations:
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/02-hoststubgen-test-tiny-framework-host-stub-dump.txt b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/02-hoststubgen-test-tiny-framework-host-stub-dump.txt
index 37de857..c605f76 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/02-hoststubgen-test-tiny-framework-host-stub-dump.txt
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/02-hoststubgen-test-tiny-framework-host-stub-dump.txt
@@ -1554,7 +1554,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 1, methods: 9, attributes: 3
+  interfaces: 0, fields: 1, methods: 10, attributes: 3
   int value;
     descriptor: I
     flags: (0x0000)
@@ -1686,6 +1686,15 @@
         com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static native byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative.java"
 RuntimeVisibleAnnotations:
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/03-hoststubgen-test-tiny-framework-host-impl-dump.txt b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/03-hoststubgen-test-tiny-framework-host-impl-dump.txt
index c9c607c..11d5939 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/03-hoststubgen-test-tiny-framework-host-impl-dump.txt
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/03-hoststubgen-test-tiny-framework-host-impl-dump.txt
@@ -2236,7 +2236,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 1, methods: 10, attributes: 3
+  interfaces: 0, fields: 1, methods: 11, attributes: 3
   int value;
     descriptor: I
     flags: (0x0000)
@@ -2435,6 +2435,23 @@
         com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=2, locals=2, args_size=2
+         x: iload_0
+         x: iload_1
+         x: invokestatic  #x                 // Method com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.nativeBytePlus:(BB)B
+         x: ireturn
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenProcessedAsSubstitute
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative.java"
 RuntimeVisibleAnnotations:
@@ -2457,7 +2474,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 0, methods: 4, attributes: 3
+  interfaces: 0, fields: 0, methods: 5, attributes: 3
   public com.android.hoststubgen.test.tinyframework.TinyFrameworkNative_host();
     descriptor: ()V
     flags: (0x0001) ACC_PUBLIC
@@ -2551,6 +2568,31 @@
     RuntimeVisibleAnnotations:
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=4, locals=2, args_size=2
+         x: ldc           #x                 // String com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
+         x: ldc           #x                 // String nativeBytePlus
+         x: ldc           #x                 // String (BB)B
+         x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.getStackWalker:()Ljava/lang/StackWalker;
+         x: invokevirtual #x                 // Method java/lang/StackWalker.getCallerClass:()Ljava/lang/Class;
+        x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.onNonStubMethodCalled:(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Class;)V
+        x: iload_0
+        x: iload_1
+        x: iadd
+        x: i2b
+        x: ireturn
+      LineNumberTable:
+      LocalVariableTable:
+        Start  Length  Slot  Name   Signature
+           15       5     0  arg1   B
+           15       5     1  arg2   B
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative_host.java"
 RuntimeVisibleAnnotations:
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/12-hoststubgen-test-tiny-framework-host-ext-stub-dump.txt b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/12-hoststubgen-test-tiny-framework-host-ext-stub-dump.txt
index 37de857..c605f76 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/12-hoststubgen-test-tiny-framework-host-ext-stub-dump.txt
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/12-hoststubgen-test-tiny-framework-host-ext-stub-dump.txt
@@ -1554,7 +1554,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 1, methods: 9, attributes: 3
+  interfaces: 0, fields: 1, methods: 10, attributes: 3
   int value;
     descriptor: I
     flags: (0x0000)
@@ -1686,6 +1686,15 @@
         com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static native byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative.java"
 RuntimeVisibleAnnotations:
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/13-hoststubgen-test-tiny-framework-host-ext-impl-dump.txt b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/13-hoststubgen-test-tiny-framework-host-ext-impl-dump.txt
index a57907d..088bc80 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/13-hoststubgen-test-tiny-framework-host-ext-impl-dump.txt
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/golden-output/13-hoststubgen-test-tiny-framework-host-ext-impl-dump.txt
@@ -2743,7 +2743,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 1, methods: 11, attributes: 3
+  interfaces: 0, fields: 1, methods: 12, attributes: 3
   int value;
     descriptor: I
     flags: (0x0000)
@@ -3002,6 +3002,28 @@
         com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=4, locals=2, args_size=2
+         x: ldc           #x                  // class com/android/hoststubgen/test/tinyframework/TinyFrameworkNative
+         x: ldc           #x                // String nativeBytePlus
+         x: ldc           #x                // String (BB)B
+         x: ldc           #x                 // String com.android.hoststubgen.hosthelper.HostTestUtils.logMethodCall
+         x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.callMethodCallHook:(Ljava/lang/Class;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V
+        x: iload_0
+        x: iload_1
+        x: invokestatic  #x                // Method com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.nativeBytePlus:(BB)B
+        x: ireturn
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenProcessedAsSubstitute
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInStub
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative.java"
 RuntimeVisibleAnnotations:
@@ -3024,7 +3046,7 @@
   flags: (0x0021) ACC_PUBLIC, ACC_SUPER
   this_class: #x                          // com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
   super_class: #x                         // java/lang/Object
-  interfaces: 0, fields: 0, methods: 5, attributes: 3
+  interfaces: 0, fields: 0, methods: 6, attributes: 3
   private static {};
     descriptor: ()V
     flags: (0x000a) ACC_PRIVATE, ACC_STATIC
@@ -3148,6 +3170,36 @@
     RuntimeVisibleAnnotations:
       x: #x()
         com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
+
+  public static byte nativeBytePlus(byte, byte);
+    descriptor: (BB)B
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=4, locals=2, args_size=2
+         x: ldc           #x                  // class com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
+         x: ldc           #x                 // String nativeBytePlus
+         x: ldc           #x                 // String (BB)B
+         x: ldc           #x                 // String com.android.hoststubgen.hosthelper.HostTestUtils.logMethodCall
+         x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.callMethodCallHook:(Ljava/lang/Class;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V
+        x: ldc           #x                 // String com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host
+        x: ldc           #x                 // String nativeBytePlus
+        x: ldc           #x                 // String (BB)B
+        x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.getStackWalker:()Ljava/lang/StackWalker;
+        x: invokevirtual #x                 // Method java/lang/StackWalker.getCallerClass:()Ljava/lang/Class;
+        x: invokestatic  #x                 // Method com/android/hoststubgen/hosthelper/HostTestUtils.onNonStubMethodCalled:(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Class;)V
+        x: iload_0
+        x: iload_1
+        x: iadd
+        x: i2b
+        x: ireturn
+      LineNumberTable:
+      LocalVariableTable:
+        Start  Length  Slot  Name   Signature
+           26       5     0  arg1   B
+           26       5     1  arg2   B
+    RuntimeVisibleAnnotations:
+      x: #x()
+        com.android.hoststubgen.hosthelper.HostStubGenKeptInImpl
 }
 SourceFile: "TinyFrameworkNative_host.java"
 RuntimeVisibleAnnotations:
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative.java b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative.java
index 5a5e22d..09ee183 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative.java
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative.java
@@ -52,4 +52,6 @@
     public static void nativeStillNotSupported_should_be_like_this() {
         throw new RuntimeException();
     }
+
+    public static native byte nativeBytePlus(byte arg1, byte arg2);
 }
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.java b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.java
index 749ebaa..b23c216 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.java
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-framework/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkNative_host.java
@@ -34,4 +34,8 @@
     public static int nativeNonStaticAddToValue(TinyFrameworkNative source, int arg) {
         return source.value + arg;
     }
+
+    public static byte nativeBytePlus(byte arg1, byte arg2) {
+        return (byte) (arg1 + arg2);
+    }
 }
diff --git a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-test/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkClassTest.java b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-test/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkClassTest.java
index ba17c75..762180d 100644
--- a/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-test/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkClassTest.java
+++ b/tools/hoststubgen/hoststubgen/test-tiny-framework/tiny-test/src/com/android/hoststubgen/test/tinyframework/TinyFrameworkClassTest.java
@@ -154,13 +154,22 @@
     }
 
     @Test
+    public void testNativeSubstitutionLong() {
+        assertThat(TinyFrameworkNative.nativeLongPlus(1L, 2L)).isEqualTo(3L);
+    }
+
+    @Test
+    public void testNativeSubstitutionByte() {
+        assertThat(TinyFrameworkNative.nativeBytePlus((byte) 3, (byte) 4)).isEqualTo(7);
+    }
+
+    @Test
     public void testNativeSubstitutionClass_nonStatic() {
         TinyFrameworkNative instance = new TinyFrameworkNative();
         instance.setValue(5);
         assertThat(instance.nativeNonStaticAddToValue(3)).isEqualTo(8);
     }
 
-
     @Test
     public void testSubstituteNativeWithThrow() throws Exception {
         // We can't use TinyFrameworkNative.nativeStillNotSupported() directly in this class,