Remove LambdaForm$Hidden annotation from emitted code

[Yarikx]

This annotation annotates some lambda methods.
It is not preserved in runtime, so it compiles fine, but create some issues for proguard.

This annotation does not exist in JDK6/7 so can be completely removed.

Related issues:
evant/gradle-retrolambda#55
AntennaPod/AntennaPod#1117
yongjhih/RxBolts#3

[simophin]

We encountered java.lang.ClassNotFoundException: java.lang.invoke.LambdaForm$Hidden on Android 4.1 when Method.isAnnotationPresent is called on a lambda method. Looks like the virtual machine is trying to load this annotation class and fails.

[Yarikx]

@simophin With or without this fix?

[simophin]

@Yarikx I believe your PR will fix this issue. Haven't tried tho, waiting to be merged. In the mean time we just replace the lambdas with anonymous classes.

[Yarikx]

@simophin Looking at another PRs are not merged yet, I don't think it will be merged soon.

[LachlanMcKee]

@Yarikx, @simophin I have also run into this issue on Android 4.1 and 4.2. Your PR worked wonderfully!

For anyone else who runs into this issue, as this has yet to be merged, I suggest building your own JAR using this branch. I compiled the JAR using the docker container without any issues (follow the instructions here).

If you are using the Retrolambda Gradle plugin, follow the instructions found here to use the local JAR instead.

[luontola]

Thanks.

I changed the code to only search for the LambdaForm$Hidden annotation inside the generated lambda classes instead of all classes. I'm assuming that the annotation doesn't appear anywhere else.

[luontola]

This has been included in Retrolambda 2.4.0. Sorry about taking so long to merge.