JMXFetch loading threw permission errors

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/DatadogClassLoader.java

@@ -10,6 +10,7 @@ import java.net.URLClassLoader;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
 import java.nio.file.NoSuchFileException;
+import java.security.Permission;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.jar.JarEntry;
@@ -148,10 +149,16 @@ public class DatadogClassLoader extends URLClassLoader {
 
     @Override
     protected URLConnection openConnection(final URL url) throws IOException {
+      if (url.getFile().equals("/")) {
+        // "/" is used as the default url of the jar
+        // This is called by the SecureClassLoader trying to obtain permissions
+        return new InternalJarURLConnection(url, new byte[] {});
+      }
+
       final byte[] bytes = filenameToBytes.get(url.getFile());
 
       if (bytes == null) {
-        throw new NoSuchFileException(url.getFile());
+        throw new NoSuchFileException(url.getFile(), null, url.getFile() + " not in internal jar");
       }
 
       return new InternalJarURLConnection(url, bytes);
@@ -175,6 +182,12 @@ public class DatadogClassLoader extends URLClassLoader {
     public InputStream getInputStream() throws IOException {
       return new ByteArrayInputStream(bytes);
     }
+
+    @Override
+    public Permission getPermission() {
+      // No permissions needed because all classes are in memory
+      return null;
+    }
   }
 
   /**

dd-java-agent/src/main/java/datadog/trace/agent/TracingAgent.java

@@ -53,23 +53,29 @@ public class TracingAgent {
       final Method registerCallbackMethod =
           agentInstallerClass.getMethod("registerClassLoadCallback", String.class, Runnable.class);
       registerCallbackMethod.invoke(
-          null,
-          "java.util.logging.LogManager",
-          new Runnable() {
-            @Override
-            public void run() {
-              try {
-                startJmxFetch(inst);
-              } catch (final Exception e) {
-                throw new RuntimeException(e);
-              }
-            }
-          });
+          null, "java.util.logging.LogManager", new LoggingCallback(inst));
     } else {
       startJmxFetch(inst);
     }
   }
 
+  protected static class LoggingCallback implements Runnable {
+    private final Instrumentation inst;
+
+    public LoggingCallback(final Instrumentation inst) {
+      this.inst = inst;
+    }
+
+    @Override
+    public void run() {
+      try {
+        startJmxFetch(inst);
+      } catch (final Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+  }
+
   public static synchronized void startDatadogAgent(final Instrumentation inst) throws Exception {
     installBootstrapJar(inst);
     if (AGENT_CLASSLOADER == null) {