lambda's in files on bootclasspath

[johanvos]

First of all, thanks for this great project.
I'm trying to apply retrolambda to the OpenJFX codebase containing the JavaFX classes. Currently, the Android port of OpenJFX uses a backported version of the JavaFX sources, and we're now trying to build everything from the latest OpenJFX sources.
The issue I have is that the JavaFX files we try to de-lambdafy are also in the boot classpath (they are in jre/lib/ext/jfxrt.jar). If I remove jfxrt.jar from the Java 8 SDK, the retrolambda process works fine.

However, when jfxrt.jar is present, there are issues since the JavaFX class files can be loaded by 2 classloaders (system classloader and the classloader scanning the retrolambda.inputDir). I tried to bypass this by prepending the bootclasspath with the javafx classes we want to process, e.g.:
java -Xbootclasspath/p:in -Dretrolambda.inputDir=in -Dretrolambda.outputDir=out -Dretrolambda.classpath=in -javaagent:retrolambda.jar -jar retrolambda.jar

But that doesn't work since the classes are then ignored, since LambdaSavingClassFileTransformer.transform() will skip classes on the System classloader

More info on this issue is available at
http://mail.openjdk.java.net/pipermail/openjfx-dev/2014-June/014217.html

[luontola]

Hmm. Some options come to my mind:

1. Use some include/exclude patterns for defining the packages from which lambdas are backported.
   • Requires extra configuration from users, which is not desirable.
2. Make it so that all classloaders are equal, and Retrolambda will check from the file system whether the class came from the input directory.
   • Lambda classes do not exists as files, so it would have to detect the enclosing class based on the class name.
3. LambdaReifier#reifyLambdaClass could communicate to the LambdaSavingClassFileTransformer that this is a lambda class that we want to save.

• Should work and be reliable.

I'm leaning towards option 3.

[johanvos]

I agree with your remarks. Option 3 is probably the best one. For now, I'm removing the jfxrt.jar from the SDK in order to use retrolambda on the JavaFX classes in OpenJFX and that works fine, so there is no pressure for this issue ;)

Thanks.

[luontola]

This has been included in Retrolambda 1.4.0

[luontola]

Please try if version 1.4.0 works for your use case - I didn't test it.