Fix muzzle

buildSrc/src/main/groovy/MuzzlePlugin.groovy

@@ -135,7 +135,6 @@ class MuzzlePlugin implements Plugin<Project> {
         }
         def loader = new URLClassLoader(ddUrls.toArray(new URL[0]), (ClassLoader) null)
         assert TOOLING_LOADER.compareAndSet(null, loader)
-        loader.loadClass("datadog.trace.agent.tooling.AgentTooling").getMethod("init").invoke(null)
         return TOOLING_LOADER.get()
       } else {
         return toolingLoader
@@ -293,7 +292,9 @@ class MuzzlePlugin implements Plugin<Project> {
         def ccl = Thread.currentThread().contextClassLoader
         def bogusLoader = new SecureClassLoader() {
           @Override
-          String toString() { return "bogus" }
+          String toString() {
+            return "bogus"
+          }
         }
         Thread.currentThread().contextClassLoader = bogusLoader
         final ClassLoader userCL = createClassLoaderForTask(instrumentationProject, bootstrapProject, taskName)

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/AgentTooling.java

@@ -8,20 +8,15 @@ import datadog.trace.bootstrap.WeakMap;
  * logic out.
  */
 public class AgentTooling {
-  private static final Cleaner CLEANER = new Cleaner();
 
   static {
     // WeakMap is used by other classes below, so we need to register the provider first.
-    registerWeakMapProvider(CLEANER);
+    registerWeakMapProvider();
   }
 
   private static final DDLocationStrategy LOCATION_STRATEGY = new DDLocationStrategy();
   private static final DDCachingPoolStrategy POOL_STRATEGY = new DDCachingPoolStrategy();
 
-  public static void init() {
-    // Only need to trigger static initializers for now.
-  }
-
   public static DDLocationStrategy locationStrategy() {
     return LOCATION_STRATEGY;
   }
@@ -30,9 +25,9 @@ public class AgentTooling {
     return POOL_STRATEGY;
   }
 
-  private static void registerWeakMapProvider(final Cleaner cleaner) {
+  private static void registerWeakMapProvider() {
     if (!WeakMap.Provider.isProviderRegistered()) {
-      WeakMap.Provider.registerIfAbsent(new WeakMapSuppliers.WeakConcurrent(cleaner));
+      WeakMap.Provider.registerIfAbsent(new WeakMapSuppliers.WeakConcurrent(new Cleaner()));
       //    WeakMap.Provider.registerIfAbsent(new WeakMapSuppliers.WeakConcurrent.Inline());
       //    WeakMap.Provider.registerIfAbsent(new WeakMapSuppliers.Guava());
     }

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/muzzle/MuzzleVersionScanPlugin.java

@@ -1,6 +1,5 @@
 package datadog.trace.agent.tooling.muzzle;
 
-import datadog.trace.agent.tooling.AgentTooling;
 import datadog.trace.agent.tooling.HelperInjector;
 import datadog.trace.agent.tooling.Instrumenter;
 import java.io.IOException;
@@ -20,9 +19,6 @@ import net.bytebuddy.dynamic.ClassFileLocator;
  * <p>Additionally, after a successful muzzle validation run each instrumenter's helper injector.
  */
 public class MuzzleVersionScanPlugin {
-  static {
-    AgentTooling.init();
-  }
 
   public static void assertInstrumentationMuzzled(
       final ClassLoader instrumentationLoader,

dd-java-agent/agent-tooling/src/test/groovy/datadog/trace/agent/tooling/WeakConcurrentSupplierTest.groovy

@@ -9,13 +9,13 @@ import spock.lang.Shared
 import java.lang.ref.WeakReference
 import java.util.concurrent.TimeUnit
 
-import static datadog.trace.agent.tooling.AgentTooling.CLEANER
-
 @Retry
 // These tests fail sometimes in CI.
 class WeakConcurrentSupplierTest extends DDSpecification {
   @Shared
-  def weakConcurrentSupplier = new WeakMapSuppliers.WeakConcurrent(CLEANER)
+  def cleaner = new Cleaner()
+  @Shared
+  def weakConcurrentSupplier = new WeakMapSuppliers.WeakConcurrent(cleaner)
   @Shared
   def weakInlineSupplier = new WeakMapSuppliers.WeakConcurrent.Inline()
   @Shared
@@ -59,7 +59,7 @@ class WeakConcurrentSupplierTest extends DDSpecification {
 
     where:
     name             | supplierSupplier
-    "WeakConcurrent" | { -> new WeakMapSuppliers.WeakConcurrent(CLEANER) }
+    "WeakConcurrent" | { -> new WeakMapSuppliers.WeakConcurrent(cleaner) }
     "WeakInline"     | { -> new WeakMapSuppliers.WeakConcurrent.Inline() }
     "Guava"          | { -> new WeakMapSuppliers.Guava() }
   }

utils/thread-utils/src/main/java/datadog/common/exec/DaemonThreadFactory.java

@@ -13,7 +13,7 @@ public final class DaemonThreadFactory implements ThreadFactory {
   private final String threadName;
 
   /**
-   * Constructs a new {@code DaemonThreadFactory}.
+   * Constructs a new {@code DaemonThreadFactory} with a null ContextClassLoader.
    *
    * @param threadName used to prefix all thread names.
    */
@@ -25,6 +25,7 @@ public final class DaemonThreadFactory implements ThreadFactory {
   public Thread newThread(final Runnable r) {
     final Thread thread = new Thread(r, threadName);
     thread.setDaemon(true);
+    thread.setContextClassLoader(null);
     return thread;
   }
 }