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This issue is supposed to serve as reference for all Jack bugs, that makes it incompatible with AIDL2 (those are actually bugs in Jack/ECJ, not in AIDL2, hence no need to create separate issues).

• Types.asMemberOf does not (really) work
  • A bug in ECJ — https://bugs.eclipse.org/bugs/show_bug.cgi?id=499026
  • A more descriptive, but already closed bug — https://bugs.eclipse.org/bugs/show_bug.cgi?id=382590
  • Google issue
• Types.capture and Types.contains are placeholders, throwing UnsupportedOperationException. As consequence, types with wildcards won't work
  • Google issue

Right now a method with N Serializable/Externalizable parameters will create and immediately throw away N ObjectXXXStream instances during each transaction. Instead it should be possible to reuse those.

It may sometimes be desirable to reuse those (especially when reasonable performance is expected).

In ideal world the following snippet would both compile and be inspectable from annotation processors:

void methodWithListParameter(List<@NonNull ? extends CustomParcelable>);

In reality ECJ does not appear to recognize type annotations as anything, but opaque source code tokens, and so does Javac.

Current situation

There is a way to make introspection on type annotations "work" in Javac:

1. Postpone your compilation until type analysis completes using Oracle-proprietary JavacTask API
2. Obtain the annotated type using Oracle proprietary Trees.getTypeMirror API.

Unfortunately, as of Javac 1.8.0_112 doing this requires significant effort (manually walking trees using tree API) and does not really work for any types, only for simple, non-composite types. The following TreePath will have no annotations:

List<@NonNull ? extends CustomParcelable>

You will have to cast it to parametrized tree and walk down to

@NonNull ? extends CustomParcelable

For which Trees.getTypeMirror will finally produce correctly annotated WildcardType.

The alternative is to use non-documented Javac classes, which will likely become unavailable in Java 9. And that still does not guarantee correct outcome.

Oncoming improvements

Javac have had a major injection of code to actually support type annotations. That code isn't included in Java 8 and will be available in Java 9 only.