Default flag --experimental_j2objc_annotation_processing to true.

--
MOS_MIGRATED_REVID=140369825
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
index efd1d11..5278fe3 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
@@ -52,7 +52,7 @@
   public boolean explicitJreDeps;
 
   @Option(name = "experimental_j2objc_annotation_processing",
-      defaultValue = "false",
+      defaultValue = "true",
       category = "undocumented",
       help = "Whether to enable j2objc Java annotation processing."
       )