Fix java9 test setup

.circleci/save_artifacts.sh

@@ -32,6 +32,7 @@ function save_libs () {
 
 save_reports dd-java-agent
 save_reports dd-java-agent/tooling
+save_reports dd-java-agent/testing
 # Save reports for all instrumentation projects
 for integration_path in dd-java-agent/instrumentation/*; do
     save_reports $integration_path

dd-java-agent/testing/src/main/java/datadog/trace/agent/test/SpockRunner.java

@@ -6,6 +6,8 @@ import com.google.common.reflect.ClassPath;
 import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.Field;
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
@@ -96,7 +98,24 @@ public class SpockRunner extends Sputnik {
   }
 
   private static File createBootstrapJar() throws IOException {
-    final ClassLoader loader = AgentTestRunner.class.getClassLoader();
+    ClassLoader loader = AgentTestRunner.class.getClassLoader();
+    if (!(loader instanceof URLClassLoader)) {
+      // java9's system loader does not extend URLClassLoader
+      // which breaks google ClassPath lookup
+      Field f = null;
+      try {
+        f = loader.getClass().getDeclaredField("ucp");
+        f.setAccessible(true);
+        Object ucp = f.get(loader);
+        loader = new URLClassLoader((URL[]) ucp.getClass().getMethod("getURLs").invoke(ucp), null);
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      } finally {
+        if (null != f) {
+          f.setAccessible(false);
+        }
+      }
+    }
     final ClassPath testCP = ClassPath.from(loader);
     Set<String> bootstrapClasses = new HashSet<String>();
     for (ClassPath.ClassInfo info : testCP.getAllClasses()) {

dd-java-agent/testing/src/test/groovy/AgentTestRunnerTest.groovy

@@ -6,20 +6,19 @@ import datadog.trace.agent.test.AgentTestRunner
 
 class AgentTestRunnerTest extends AgentTestRunner {
   private static final ClassLoader BOOTSTRAP_CLASSLOADER = null
-  private static final boolean OT_LOADED_IN_CLINIT
+  private static final ClassLoader OT_LOADER
   private static final boolean AGENT_INSTALLED_IN_CLINIT
 
   static {
     // when test class initializes, opentracing should be set up, but not the agent.
-    OT_LOADED_IN_CLINIT = io.opentracing.Tracer.getClassLoader() == BOOTSTRAP_CLASSLOADER
+    OT_LOADER = io.opentracing.Tracer.getClassLoader()
     AGENT_INSTALLED_IN_CLINIT = getAgentTransformer() != null
   }
 
   def "classpath setup"() {
     expect:
-    OT_LOADED_IN_CLINIT
+    OT_LOADER == BOOTSTRAP_CLASSLOADER
     !AGENT_INSTALLED_IN_CLINIT
-    io.opentracing.Tracer.getClassLoader() == BOOTSTRAP_CLASSLOADER
     TEST_TRACER == TestUtils.getUnderlyingGlobalTracer()
     getAgentTransformer() != null
     datadog.trace.api.Trace.getClassLoader() == BOOTSTRAP_CLASSLOADER

gradle/java.gradle

@@ -114,3 +114,11 @@ plugins.withType(BasePlugin) {
     otherTasks*.mustRunAfter deleteTasks
   }
 }
+
+if (JavaVersion.current().isJava9Compatible()) {
+  // required to allow reflection into java9 for testing
+  test {
+    jvmArgs '--add-opens'
+    jvmArgs 'java.base/jdk.internal.loader=ALL-UNNAMED'
+  }
+}