Snap for 11582845 from 88a62bb6769aa02fba887a969041572fab07e6f7 to build-tools-releasebuild-tools-release

Change-Id: Ib851e35bca84c8e2d1b89e388ea8e9446bab50b6

11 files changed, 565 insertions, 49 deletions

diff --git a/Android.bp b/Android.bp
index 67d9d24a4..fffaeb0f6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -29,7 +29,16 @@ java_library_host {
     name: "javac_extractor",
     srcs: [
         "kythe/java/com/google/devtools/kythe/extractors/java/standalone/AbstractJavacWrapper.java",
-        "kythe/java/com/google/devtools/kythe/extractors/java/standalone/Javac9Wrapper.java",
+        "kythe/java/com/google/devtools/kythe/extractors/java/standalone/JavacWrapper.java",
+        "kythe/java/com/google/devtools/kythe/extractors/java/standalone/JdkCompatibilityShims.java",
+        // Currently it is not possible to pick a specific JDK version implementation of
+        // JdkCompatibilityShim, so only use the fallback (reflective) one. Otherwise, if it becomes
+        // possible, either through bp file configuration, or once JDK 21 is used consistently, we
+        // could also select one the options below.
+        "kythe/java/com/google/devtools/kythe/extractors/java/standalone/ReflectiveJdkCompatibilityShims.java",
+        // "kythe/java/com/google/devtools/kythe/extractors/java/standalone/9/JdkCompatibilityShimsImpl.java",
+        // "kythe/java/com/google/devtools/kythe/extractors/java/standalone/15/JdkCompatibilityShimsImpl.java",
+        // "kythe/java/com/google/devtools/kythe/extractors/java/standalone/21/JdkCompatibilityShimsImpl.java",
         "kythe/java/com/google/devtools/kythe/extractors/java/*.java",
         "kythe/java/com/google/devtools/kythe/extractors/shared/*.java",
         "kythe/java/com/google/devtools/kythe/platform/kzip/*.java",
@@ -38,6 +47,7 @@ java_library_host {
         "kythe/java/com/google/devtools/kythe/platform/shared/CompilationUnits.java",
         "kythe/java/com/google/devtools/kythe/util/DeleteRecursively.java",
         "kythe/java/com/google/devtools/kythe/util/JsonUtil.java",
+        "kythe/java/com/google/devtools/kythe/util/OrderedCompatibilityService.java",
         ":kythe_protos",
         "kythe/proto/java.proto",
     ],
@@ -48,7 +58,10 @@ java_library_host {
         "--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
         "--add-exports jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
         "--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
+        "--add-exports=jdk.internal.opt/jdk.internal.opt=ALL-UNNAMED",
         "--add-modules java.compiler",
+        "--add-modules jdk.internal.opt",
     ],
     manifest: "javac_extractor_manifest.txt",
     proto: {
@@ -65,6 +78,10 @@ java_library_host {
         "libprotobuf-java-util-full",
         "guava",
         "jsr305",
+        "auto_service_annotations",
+    ],
+    plugins: [
+        "auto_service_plugin",
     ],
     java_version: "1.9",
 }
diff --git a/javac_extractor_manifest.txt b/javac_extractor_manifest.txt
index 7e039cc35..d30b75ecc 100644
--- a/javac_extractor_manifest.txt
+++ b/javac_extractor_manifest.txt
@@ -1 +1 @@
-Main-Class: com.google.devtools.kythe.extractors.java.standalone.Javac9Wrapper
+Main-Class: com.google.devtools.kythe.extractors.java.standalone.JavacWrapper
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/15/JdkCompatibilityShimsImpl.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/15/JdkCompatibilityShimsImpl.java
new file mode 100644
index 000000000..e0be7547f
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/15/JdkCompatibilityShimsImpl.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.extractors.java.standalone;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.Lists;
+import com.sun.tools.javac.main.Arguments;
+import com.sun.tools.javac.main.CommandLine;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+/** JdkCompatibilityShims implementation for JDK15-compatible releases. */
+@AutoService(JdkCompatibilityShims.class)
+public final class JdkCompatibilityShimsImpl implements JdkCompatibilityShims {
+  private static final Runtime.Version minVersion = Runtime.Version.parse("15");
+  private static final Runtime.Version maxVersion = Runtime.Version.parse("21");
+
+  public JdkCompatibilityShimsImpl() {}
+
+  @Override
+  public CompatibilityRange getCompatibleRange() {
+    return new CompatibilityRange(minVersion, maxVersion);
+  }
+
+  @Override
+  public List<String> parseCompilerArguments(String[] args) throws IOException {
+    return Lists.newArrayList(CommandLine.parse(Arrays.asList(args)));
+  }
+
+  @Override
+  public void initializeArguments(Arguments arguments, String[] args) {
+    arguments.init("kythe_javac", Arrays.asList(args));
+  }
+}
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/21/JdkCompatibilityShimsImpl.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/21/JdkCompatibilityShimsImpl.java
new file mode 100644
index 000000000..a90082ed4
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/21/JdkCompatibilityShimsImpl.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2023 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.extractors.java.standalone;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.Lists;
+import com.sun.tools.javac.main.Arguments;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import jdk.internal.opt.CommandLine;
+
+/** JdkCompatibilityShims implementation for JDK21-compatible releases. */
+@AutoService(JdkCompatibilityShims.class)
+public final class JdkCompatibilityShimsImpl implements JdkCompatibilityShims {
+  private static final Runtime.Version minVersion = Runtime.Version.parse("21");
+
+  public JdkCompatibilityShimsImpl() {}
+
+  @Override
+  public CompatibilityRange getCompatibleRange() {
+    return new CompatibilityRange(minVersion);
+  }
+
+  @Override
+  public List<String> parseCompilerArguments(String[] args) throws IOException {
+    return Lists.newArrayList(CommandLine.parse(Arrays.asList(args)));
+  }
+
+  @Override
+  public void initializeArguments(Arguments arguments, String[] args) {
+    arguments.init("kythe_javac", Arrays.asList(args));
+  }
+}
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/9/JdkCompatibilityShimsImpl.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/9/JdkCompatibilityShimsImpl.java
new file mode 100644
index 000000000..45f41ee47
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/9/JdkCompatibilityShimsImpl.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.extractors.java.standalone;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.Lists;
+import com.sun.tools.javac.main.Arguments;
+import com.sun.tools.javac.main.CommandLine;
+import java.io.IOException;
+import java.util.List;
+
+/** JdkCompatibilityShims implementation for JDK9-compatible releases. */
+@AutoService(JdkCompatibilityShims.class)
+public final class JdkCompatibilityShimsImpl implements JdkCompatibilityShims {
+  private static final Runtime.Version minVersion = Runtime.Version.parse("9");
+  private static final Runtime.Version maxVersion = Runtime.Version.parse("15");
+
+  public JdkCompatibilityShimsImpl() {}
+
+  @Override
+  public CompatibilityRange getCompatibleRange() {
+    return new CompatibilityRange(minVersion, maxVersion);
+  }
+
+  @Override
+  public List<String> parseCompilerArguments(String[] args) throws IOException {
+    return Lists.newArrayList(CommandLine.parse(args));
+  }
+
+  @Override
+  public void initializeArguments(Arguments arguments, String[] args) {
+    arguments.init("kythe_javac", args);
+  }
+}
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/AbstractJavacWrapper.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/AbstractJavacWrapper.java
index 0c883ac6d..3a84d4a05 100644
--- a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/AbstractJavacWrapper.java
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/AbstractJavacWrapper.java
@@ -31,7 +31,6 @@ import com.google.devtools.kythe.extractors.shared.IndexInfoUtils;
 import com.google.devtools.kythe.proto.Analysis.CompilationUnit;
 import com.google.devtools.kythe.proto.Analysis.FileData;
 import com.google.devtools.kythe.util.JsonUtil;
-import com.sun.tools.javac.main.CommandLine;
 import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
@@ -66,6 +65,7 @@ import java.util.Optional;
  */
 public abstract class AbstractJavacWrapper {
   private static final Logger logger = Logger.getLogger(AbstractJavacWrapper.class.getName());
+  protected static final JdkCompatibilityShims shims = JdkCompatibilityShims.loadBest().get();
 
   protected abstract Collection<CompilationDescription> processCompilation(
       String[] arguments, JavaCompilationUnitExtractor javaCompilationUnitExtractor)
@@ -150,26 +150,7 @@ public abstract class AbstractJavacWrapper {
 
   private static String[] getCleanedUpArguments(String[] args) throws IOException {
     // Expand all @file arguments
-    // JDK changed the signature of the CommandLine.parse method in JDK15,
-    // support both versions
-    List<String> expandedArgs = null;
-    try {
-      try {
-        // JDK15+: the signature is
-        //     List<String> parse(List<String> args);
-        expandedArgs = (List<String>)CommandLine.class.getMethod("parse", List.class).invoke(null, (Object)Arrays.asList(args));
-      } catch (NoSuchMethodException nsme) {
-        // pre-JDK15:
-        //     String[] parse(String[]);
-        expandedArgs = Arrays.asList((String[])CommandLine.class.getMethod("parse", String[].class).invoke(null, (Object)args));
-      }
-    } catch (NoSuchMethodException ns2) {
-      System.err.printf("Cannot locate com.sun.tools.javac.main.CommandLine.parse method, JDK version %s\n", System.getProperty("java.version"));
-      System.exit(2);
-    } catch (InvocationTargetException|IllegalAccessException ex) {
-      System.err.printf("Cannot call com.sun.tools.javac.main.CommandLine.parse (JDK version %s):\n%s\n", System.getProperty("java.version"), ex);
-      System.exit(2);
-    }
+    List<String> expandedArgs = shims.parseCompilerArguments(args);
 
     // We skip some arguments that would normally be passed to javac:
     // -J, these are flags to the java environment running javac.
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/BUILD b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/BUILD
index 8b1a2f9f4..c118ef17a 100644
--- a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/BUILD
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/BUILD
@@ -1,5 +1,6 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load("@rules_java//java:defs.bzl", "java_binary", "java_library")
+load("//tools:build_rules/selects.bzl", select_with_or = "with_or")
 
 package(default_visibility = ["//kythe:default_visibility"])
 
@@ -7,13 +8,21 @@ exports_files(["javac-wrapper.sh"])
 
 java_binary(
     name = "javac_extractor",
-    srcs = ["Javac9Wrapper.java"],
+    srcs = ["JavacWrapper.java"],
     javacopts = [
         "--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
         "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
         "--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
     ],
-    main_class = "com.google.devtools.kythe.extractors.java.standalone.Javac9Wrapper",
+    jvm_flags = [
+        "--add-exports=jdk.internal.opt/jdk.internal.opt=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+    ],
+    main_class = "com.google.devtools.kythe.extractors.java.standalone.JavacWrapper",
     visibility = ["//visibility:public"],
     deps = [
         ":abstract_javac_wrapper",
@@ -31,7 +40,22 @@ java_library(
     javacopts = [
         "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
     ],
+    runtime_deps = [
+        ":reflective_jdk_compatibility_shims",
+    ] + select_with_or({
+        (
+            "//buildenv/java:language_version_default",
+            "//buildenv/java:language_version_11",
+        ): [":jdk9_compatibility_shims"],
+        (
+            "//buildenv/java:language_version_17",
+            "//buildenv/java:language_version_19",
+            "//buildenv/java:language_version_20",
+            "//buildenv/java:language_version_21",
+        ): [":jdk15_compatibility_shims"],
+    }),
     deps = [
+        ":jdk_compatibility_shims",
         "//kythe/java/com/google/devtools/kythe/extractors/java",
         "//kythe/java/com/google/devtools/kythe/extractors/shared",
         "//kythe/java/com/google/devtools/kythe/extractors/shared:environment",
@@ -43,7 +67,115 @@ java_library(
     ],
 )
 
+java_library(
+    name = "jdk_compatibility_shims",
+    srcs = ["JdkCompatibilityShims.java"],
+    javacopts = [
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+    ],
+    visibility = ["//visibility:private"],
+    deps = ["//kythe/java/com/google/devtools/kythe/util:ordered_compatibility_service"],
+)
+
+java_library(
+    name = "jdk9_compatibility_shims",
+    srcs = ["9/JdkCompatibilityShimsImpl.java"],
+    javacopts = [
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+        "-Xep:PackageLocation:OFF",
+    ],
+    target_compatible_with = select_with_or({
+        (
+            "//buildenv/java:language_version_default",
+            "//buildenv/java:language_version_11",
+        ): [],
+        "//conditions:default": ["@platforms//:incompatible"],
+    }),
+    visibility = ["//visibility:private"],
+    deps = [
+        ":jdk_compatibility_shims",
+        "//kythe/java/com/google/devtools/kythe/common:autoservice",
+        "//kythe/java/com/google/devtools/kythe/util:ordered_compatibility_service",
+        "//third_party/guava",
+    ],
+)
+
+java_library(
+    name = "jdk15_compatibility_shims",
+    srcs = ["15/JdkCompatibilityShimsImpl.java"],
+    javacopts = [
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+        "-Xep:PackageLocation:OFF",
+    ],
+    # This is incompatible with the default test configuration and
+    # bazel cquery doesn't work with objc_library targets.
+    tags = ["manual"],
+    target_compatible_with = select_with_or({
+        (
+            "//buildenv/java:language_version_17",
+            "//buildenv/java:language_version_19",
+            "//buildenv/java:language_version_20",
+        ): [],
+        "//conditions:default": ["@platforms//:incompatible"],
+    }),
+    visibility = ["//visibility:private"],
+    deps = [
+        ":jdk_compatibility_shims",
+        "//kythe/java/com/google/devtools/kythe/common:autoservice",
+        "//kythe/java/com/google/devtools/kythe/util:ordered_compatibility_service",
+        "//third_party/guava",
+    ],
+)
+
+java_library(
+    name = "jdk21_compatibility_shims",
+    srcs = ["21/JdkCompatibilityShimsImpl.java"],
+    javacopts = [
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+        "--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
+        "--add-exports=jdk.internal.opt/jdk.internal.opt=ALL-UNNAMED",
+        "-Xep:PackageLocation:OFF",
+    ],
+    # This is incompatible with the default test configuration and
+    # bazel cquery doesn't work with objc_library targets.
+    tags = ["manual"],
+    target_compatible_with = select_with_or({
+        (
+            "//buildenv/java:language_version_21",
+        ): [],
+        "//conditions:default": ["@platforms//:incompatible"],
+    }),
+    visibility = ["//visibility:private"],
+    deps = [
+        ":jdk_compatibility_shims",
+        "//kythe/java/com/google/devtools/kythe/common:autoservice",
+        "//kythe/java/com/google/devtools/kythe/util:ordered_compatibility_service",
+        "//third_party/guava",
+    ],
+)
+
+java_library(
+    name = "reflective_jdk_compatibility_shims",
+    srcs = ["ReflectiveJdkCompatibilityShims.java"],
+    javacopts = [
+        "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
+    ] + select_with_or({
+        (
+            "//buildenv/java:language_version_21",
+        ): ["--add-exports=jdk.internal.opt/jdk.internal.opt=ALL-UNNAMED"],
+        "//conditions:default": [],
+    }),
+    visibility = ["//visibility:private"],
+    deps = [
+        ":jdk_compatibility_shims",
+        "//kythe/java/com/google/devtools/kythe/common:autoservice",
+        "//kythe/java/com/google/devtools/kythe/util:ordered_compatibility_service",
+        "//third_party/guava",
+    ],
+)
+
 bzl_library(
     name = "aspect_bzl",
     srcs = ["aspect.bzl"],
+    deps = ["@rules_java//java:utils"],
 )
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/Javac9Wrapper.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/JavacWrapper.java
index 31bc66a7b..291145129 100644
--- a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/Javac9Wrapper.java
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/JavacWrapper.java
@@ -37,8 +37,12 @@ import java.util.List;
 import javax.tools.JavaFileObject;
 import javax.tools.StandardLocation;
 
-/** A class that wraps javac to extract compilation information and write it to an index file. */
-public class Javac9Wrapper extends AbstractJavacWrapper {
+/**
+ * A class that wraps javac to extract compilation information and write it to an index file.
+ *
+ * <p>This class works for Java 9 and later.
+ */
+public class JavacWrapper extends AbstractJavacWrapper {
   @Override
   protected Collection<CompilationDescription> processCompilation(
       String[] arguments, JavaCompilationUnitExtractor javaCompilationUnitExtractor)
@@ -48,27 +52,7 @@ public class Javac9Wrapper extends AbstractJavacWrapper {
 
     JavacFileManager fileManager = new JavacFileManager(context, true, null);
     Arguments args = Arguments.instance(context);
-    // JDK changed the signature of Arguments.init method, support both
-    try {
-      try {
-        // JDK15+: the signature is
-        //     init(String, Iterable<String> args);
-        Arguments.class.getMethod("init", String.class, Iterable.class)
-          .invoke(args, "kythe_javac", (Object) Arrays.asList(arguments));
-      } catch (NoSuchMethodException nsme) {
-        // pre-JDK15:
-        //     init(String, String...);
-        Arguments.class.getMethod("init", String.class,String[].class)
-          .invoke(args, "kythe_javac", (Object)arguments);
-      }
-    } catch (NoSuchMethodException ns2) {
-      System.err.printf("Cannot locate com.sun.tools.javac.main.Arguments.init method, JDK version %s\n", System.getProperty("java.version"));
-      System.exit(2);
-    } catch (InvocationTargetException|IllegalAccessException ex) {
-      System.err.printf("Cannot call com.sun.tools.javac.main.Arguments.init (JDK version %s):\n%s\n", System.getProperty("java.version"), ex);
-      System.exit(2);
-    }
-
+    shims.initializeArguments(args, arguments);
     fileManager.handleOptions(args.getDeferredFileManagerOptions());
     Options options = Options.instance(context);
 
@@ -173,6 +157,6 @@ public class Javac9Wrapper extends AbstractJavacWrapper {
   }
 
   public static void main(String[] args) {
-    new Javac9Wrapper().process(args);
+    new JavacWrapper().process(args);
   }
 }
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/JdkCompatibilityShims.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/JdkCompatibilityShims.java
new file mode 100644
index 000000000..3c042c5cf
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/JdkCompatibilityShims.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2022 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.extractors.java.standalone;
+
+import com.google.devtools.kythe.util.OrderedCompatibilityService;
+import com.sun.tools.javac.main.Arguments;
+import java.io.IOException;
+import java.util.List;
+import java.util.Optional;
+
+/** Shims for providing source-level compatibility between JDK versions. */
+public interface JdkCompatibilityShims extends OrderedCompatibilityService {
+  /** Loads the best service provider for this interface, if any. */
+  public static Optional<JdkCompatibilityShims> loadBest() {
+    return OrderedCompatibilityService.loadBest(JdkCompatibilityShims.class);
+  }
+
+  /** Parse the compiler arguments and returns them as an expanded list. */
+  List<String> parseCompilerArguments(String[] args) throws IOException;
+
+  /** Initialize the Arguments instance from the list of args. */
+  void initializeArguments(Arguments arguments, String[] args);
+}
diff --git a/kythe/java/com/google/devtools/kythe/extractors/java/standalone/ReflectiveJdkCompatibilityShims.java b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/ReflectiveJdkCompatibilityShims.java
new file mode 100644
index 000000000..80dacbe2f
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/extractors/java/standalone/ReflectiveJdkCompatibilityShims.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2022 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.extractors.java.standalone;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
+import com.sun.tools.javac.main.Arguments;
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+
+/** JdkCompatibilityShims implementation for JDK9-compatible releases. */
+@AutoService(JdkCompatibilityShims.class)
+public final class ReflectiveJdkCompatibilityShims implements JdkCompatibilityShims {
+  private static final Runtime.Version minVersion = Runtime.Version.parse("9");
+
+  public ReflectiveJdkCompatibilityShims() {}
+
+  @Override
+  public CompatibilityRange getCompatibleRange() {
+    return new CompatibilityRange(minVersion, Optional.empty(), CompatibilityLevel.FALLBACK);
+  }
+
+  @Override
+  @SuppressWarnings({"CheckedExceptionNotThrown", "unchecked"}) // Safe by specification.
+  public List<String> parseCompilerArguments(String[] args) throws IOException {
+    try {
+      Class<?> commandLine = loadCommandLineClass();
+      try {
+        // JDK15+: the signature is
+        //     List<String> parse(List<String> args)
+        return (List<String>)
+            commandLine.getMethod("parse", List.class).invoke(null, (Object) Arrays.asList(args));
+      } catch (NoSuchMethodException nsme) {
+        // 9 <= JDK < 15: the signature is
+        //     String[] parse(String[] args)
+        return Arrays.asList(
+            (String[]) commandLine.getMethod("parse", String[].class).invoke(null, (Object) args));
+      }
+    } catch (ClassCastException
+        | ClassNotFoundException
+        | InvocationTargetException
+        | IllegalAccessException
+        | NoSuchMethodException ex) {
+      throw new LinkageError(ex.getMessage(), ex);
+    }
+  }
+
+  @Override
+  public void initializeArguments(Arguments arguments, String[] args) {
+    try {
+      try {
+        // JDK15+: the signature is
+        //     init(String, Iterable<String> args);
+        arguments
+            .getClass()
+            .getMethod("init", String.class, Iterable.class)
+            .invoke(arguments, "kythe_javac", (Object) Arrays.asList(args));
+      } catch (NoSuchMethodException nsme) {
+        // pre-JDK15:
+        //     init(String, String...);
+        arguments
+            .getClass()
+            .getMethod("init", String.class, String[].class)
+            .invoke(arguments, "kythe_javac", (Object) args);
+      }
+    } catch (ClassCastException
+        | InvocationTargetException
+        | IllegalAccessException
+        | NoSuchMethodException ex) {
+      throw new LinkageError(ex.getMessage(), ex);
+    }
+  }
+
+  private static Class<?> loadCommandLineClass() throws ClassNotFoundException {
+    ImmutableList<String> classNames =
+        // < JDK21 the class is known as com.sun.tools.java.main.CommandLine
+        // >= JDK21 it's known as jdk.internal.opt.CommandLine
+        ImmutableList.of("com.sun.tools.javac.main.CommandLine", "jdk.internal.opt.CommandLine");
+    for (String name : classNames) {
+      try {
+        return ReflectiveJdkCompatibilityShims.class.getClassLoader().loadClass(name);
+      } catch (ClassNotFoundException unused) {
+        continue;
+      }
+    }
+    throw new ClassNotFoundException("unable to load JDK CommandLine class");
+  }
+}
diff --git a/kythe/java/com/google/devtools/kythe/util/OrderedCompatibilityService.java b/kythe/java/com/google/devtools/kythe/util/OrderedCompatibilityService.java
new file mode 100644
index 000000000..84db8c4cd
--- /dev/null
+++ b/kythe/java/com/google/devtools/kythe/util/OrderedCompatibilityService.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2022 The Kythe Authors. All rights reserved.
+ *
+ * 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.google.devtools.kythe.util;
+
+import com.google.common.collect.Streams;
+import java.util.Comparator;
+import java.util.Optional;
+import java.util.ServiceLoader;
+
+/**
+ * OrderedCompatibilityService defines shared functionality between between JdkCompatibilityShim
+ * interfaces.
+ */
+public interface OrderedCompatibilityService {
+
+  /** The compatibility level of the provider. */
+  public enum CompatibilityLevel {
+    /** This provider is incompatible with the current runtime. */
+    INCOMPATIBLE,
+    /**
+     * This provider is compatible with the current runtime, but should only be used if a COMPATIBLE
+     * provider can't be found.
+     */
+    FALLBACK,
+    /**
+     * This provider is compatible with the current runtime and should be preferred over a fallback,
+     * if any.
+     */
+    COMPATIBLE
+  }
+
+  /** Indicates the range of runtime versions with which these shims are compatible. */
+  public static class CompatibilityRange {
+    private final Runtime.Version minVersion;
+    private final Optional<Runtime.Version> maxVersion;
+    private final CompatibilityLevel level;
+
+    public CompatibilityRange(Runtime.Version minVersion) {
+      this(minVersion, Optional.empty(), CompatibilityLevel.COMPATIBLE);
+    }
+
+    public CompatibilityRange(Runtime.Version minVersion, Runtime.Version maxVersion) {
+      this(minVersion, Optional.of(maxVersion), CompatibilityLevel.COMPATIBLE);
+    }
+
+    public CompatibilityRange(
+        Runtime.Version minVersion,
+        Optional<Runtime.Version> maxVersion,
+        CompatibilityLevel level) {
+      this.minVersion = minVersion;
+      this.maxVersion = maxVersion;
+      this.level = level;
+    }
+
+    /** Returns the minimum known compatible runtime version. */
+    public Runtime.Version getMinVersion() {
+      return minVersion;
+    }
+
+    /** Returns the maximum known compatible runtime version, if any. */
+    public Optional<Runtime.Version> getMaxVersion() {
+      return maxVersion;
+    }
+
+    /** Returns the compatibility level. */
+    public CompatibilityLevel getCompatibilityLevel() {
+      return level;
+    }
+  }
+
+  /** Returns the compatibility level of the service provider. */
+  CompatibilityRange getCompatibleRange();
+
+  public static <S extends OrderedCompatibilityService> Optional<S> loadBest(Class<S> klass) {
+    Runtime.Version version = Runtime.version();
+    return Streams.stream(ServiceLoader.load(klass))
+        // Filter out incompatible providers.
+        .filter(p -> isCompatible(version, p.getCompatibleRange()))
+        // Then find the best.
+        .max(OrderedCompatibilityService::compareProviders);
+  }
+
+  private static boolean isCompatible(Runtime.Version version, CompatibilityRange range) {
+    return range.getCompatibilityLevel() != CompatibilityLevel.INCOMPATIBLE
+        && version.compareToIgnoreOptional(range.getMinVersion()) >= 0
+        && range.getMaxVersion().map(max -> version.compareToIgnoreOptional(max) < 0).orElse(true);
+  }
+
+  private static int compareCompatibilityRanges(CompatibilityRange lhs, CompatibilityRange rhs) {
+    return Comparator.comparing(CompatibilityRange::getCompatibilityLevel)
+        .thenComparing(CompatibilityRange::getMinVersion, Runtime.Version::compareToIgnoreOptional)
+        .compare(lhs, rhs);
+  }
+
+  private static <S extends OrderedCompatibilityService> int compareProviders(S lhs, S rhs) {
+    return Comparator.comparing(
+            OrderedCompatibilityService::getCompatibleRange,
+            OrderedCompatibilityService::compareCompatibilityRanges)
+        .compare(lhs, rhs);
+  }
+}