add a null check

Author: evanchooly

dd-java-agent/instrumentation/grpc-1.5/src/main/java/datadog/trace/instrumentation/grpc/server/MethodHandlersInstrumentation.java

@@ -45,28 +45,30 @@ public static class BuildAdvice {
 
     @Advice.OnMethodEnter(suppress = Throwable.class)
     public static void onEnter(@Advice.Argument(0) Object serviceImpl) {
-      try {
-        Class<?> serviceClass = serviceImpl.getClass();
-        Class<?> superclass = serviceClass.getSuperclass();
-        Class<?> enclosingClass = superclass.getEnclosingClass();
-        Field serviceNameField = enclosingClass.getDeclaredField("SERVICE_NAME");
-        String serviceName = (String) serviceNameField.get(enclosingClass);
-        for (Method method : superclass.getDeclaredMethods()) {
-          try {
-            Method declaredMethod =
-                serviceClass.getDeclaredMethod(method.getName(), method.getParameterTypes());
-            CodeOriginInfo.entry(
-                String.format("%s/%s", serviceName, method.getName()),
-                serviceClass,
-                declaredMethod.getName(),
-                declaredMethod.getParameterTypes());
-          } catch (NoSuchMethodException e) {
-            // service method not override on the impl.  skipping instrumentation
+      Class<?> serviceClass = serviceImpl.getClass();
+      Class<?> superclass = serviceClass.getSuperclass();
+      if (superclass != null) {
+        try {
+          Class<?> enclosingClass = superclass.getEnclosingClass();
+          Field serviceNameField = enclosingClass.getDeclaredField("SERVICE_NAME");
+          String serviceName = (String) serviceNameField.get(enclosingClass);
+          for (Method method : superclass.getDeclaredMethods()) {
+            try {
+              Method declaredMethod =
+                  serviceClass.getDeclaredMethod(method.getName(), method.getParameterTypes());
+              CodeOriginInfo.entry(
+                  String.format("%s/%s", serviceName, method.getName()),
+                  serviceClass,
+                  declaredMethod.getName(),
+                  declaredMethod.getParameterTypes());
+            } catch (NoSuchMethodException e) {
+              // service method not override on the impl.  skipping instrumentation
+            }
           }
+        } catch (ReflectiveOperationException e) {
+          // need to find a way to log this
+          //        LOG.debug("Member not found.  Not instrumenting {}", serviceClass.getName(), e);
         }
-      } catch (ReflectiveOperationException e) {
-        // need to find a way to log this
-        //        LOG.debug("Member not found.  Not instrumenting {}", serviceClass.getName(), e);
       }
     }
   }

dd-java-agent/instrumentation/grpc-1.5/src/test/groovy/GrpcCodeOriginTest.groovy

@@ -222,8 +222,8 @@ abstract class GrpcCodeOriginTest extends VersionedNamingTestBase {
             codeOrigin(format(DDTags.DD_CODE_ORIGIN_FRAME, 0, "signature"))
 
             for (i in 0..<8) {
-              for (codeOrigin in ["file", "line", "method", "type"]) {
-                codeOrigin(format(DDTags.DD_CODE_ORIGIN_FRAME, i, codeOrigin))
+              for (label in ["file", "line", "method", "type"]) {
+                codeOrigin(format(DDTags.DD_CODE_ORIGIN_FRAME, i, label))
               }
             }
             defaultTags(true)