add jpms compatible class file transformer

Author: SylvainJuge

instrumentation/internal/internal-lambda/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/internal/lambda/LambdaTransformer.java

@@ -11,21 +11,11 @@
 
 /** Helper class for transforming lambda class bytes. */
 public final class LambdaTransformer {
-  private static final boolean IS_JAVA_9 = isJava9();
 
   private LambdaTransformer() {}
 
-  private static boolean isJava9() {
-    try {
-      Class.forName("java.lang.Module", false, null);
-      return true;
-    } catch (ClassNotFoundException exception) {
-      return false;
-    }
-  }
-
   /**
-   * Called from {@code java.lang.invoke.InnerClassLambdaMetafactory} to transform lambda class
+   * Called from {@code java.lang.invoke.InnerClassLambdaMetaFactory} to transform lambda class
    * bytes.
    */
   @SuppressWarnings("unused")
@@ -34,29 +24,21 @@ public static byte[] transform(byte[] classBytes, String slashClassName, Class<?
     if (InjectedClassHelper.isHelperClass(targetClass)) {
       return classBytes;
     }
-
     ClassFileTransformer transformer = ClassFileTransformerHolder.getClassFileTransformer();
-    if (transformer != null) {
-      try {
-        byte[] result;
-        if (IS_JAVA_9) {
-          result =
-              Java9LambdaTransformer.transform(
-                  transformer, classBytes, slashClassName, targetClass);
-        } else {
-          result =
-              transformer.transform(
-                  targetClass.getClassLoader(), slashClassName, null, null, classBytes);
-        }
-        if (result != null) {
-          return result;
-        }
-      } catch (Throwable throwable) {
-        // sun.instrument.TransformerManager catches Throwable from ClassFileTransformer and ignores
-        // it, we do the same.
+    if (transformer == null) {
+      return classBytes;
+    }
+    try {
+      byte[] result =
+          transformer.transform(
+              targetClass.getClassLoader(), slashClassName, targetClass, null, classBytes);
+      if (result != null) {
+        classBytes = result;
       }
+    } catch (Throwable throwable) {
+      // sun.instrument.TransformerManager catches Throwable from ClassFileTransformer and ignores
+      // it, we do the same.
     }
-
     return classBytes;
   }
 }

javaagent-tooling/javaagent-tooling-java9/src/main/java/io/opentelemetry/javaagent/tooling/JavaModuleClassFileTransformer.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.tooling;
+
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.IllegalClassFormatException;
+import java.security.ProtectionDomain;
+
+/** {@link ClassFileTransformer} implementation that provides java9 jpms module compatibility */
+public class JavaModuleClassFileTransformer implements ClassFileTransformer {
+
+  private ClassFileTransformer delegate;
+
+  public JavaModuleClassFileTransformer(ClassFileTransformer delegate) {
+    this.delegate = delegate;
+  }
+
+  @Override
+  public byte[] transform(
+      ClassLoader loader,
+      String className,
+      Class<?> targetClass,
+      ProtectionDomain protectionDomain,
+      byte[] classfileBuffer)
+      throws IllegalClassFormatException {
+
+    Module module = targetClass != null ? targetClass.getModule() : null;
+    return delegate.transform(
+        module, loader, className, targetClass, protectionDomain, classfileBuffer);
+  }
+}

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/AgentInstaller.java

@@ -48,6 +48,7 @@
 import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;
 import io.opentelemetry.sdk.autoconfigure.SdkAutoconfigureAccess;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import java.lang.instrument.ClassFileTransformer;
 import java.lang.instrument.Instrumentation;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -63,7 +64,6 @@
 import net.bytebuddy.ByteBuddy;
 import net.bytebuddy.agent.builder.AgentBuilder;
 import net.bytebuddy.agent.builder.AgentBuilderUtil;
-import net.bytebuddy.agent.builder.ResettableClassFileTransformer;
 import net.bytebuddy.description.type.TypeDefinition;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.dynamic.DynamicType;
@@ -199,9 +199,13 @@ private static void installBytebuddyAgent(
     logger.log(FINE, "Installed {0} extension(s)", numberOfLoadedExtensions);
 
     agentBuilder = AgentBuilderUtil.optimize(agentBuilder);
-    ResettableClassFileTransformer resettableClassFileTransformer = agentBuilder.installOn(inst);
+    ClassFileTransformer transformer = agentBuilder.installOn(inst);
     instrumentationInstalled = true;
-    ClassFileTransformerHolder.setClassFileTransformer(resettableClassFileTransformer);
+    if (JavaModule.isSupported()) {
+      // wrapping in a JPMS compliant implementation
+      transformer = new JavaModuleClassFileTransformer(transformer);
+    }
+    ClassFileTransformerHolder.setClassFileTransformer(transformer);
 
     addHttpServerResponseCustomizers(extensionClassLoader);