David Hill David.Hill at
Thu May 8 17:04:14 UTC 2014

On 5/8/14, May 8, 12:31 PM, Johan Vos wrote:
> Hi,
> We're getting closer to building the JavaFX Android runtime in OpenJFX.
> I'm trying to automate all steps in the gradle build files, but my
> knowledge is still very limited.
> My current bottleneck: I would like to apply retrolambda to all class files
> once they are compiled (per module). In my JavaFX Android application, this
> is easily done by following the instructions for the retrolambda-gradle
> plugin at I just add apply
> plugin: 'retrolambda' and automatically all my class files are converted
> from Java 8 to Java 7, with lambda's being replaced.
> For some reason, this doesn't work out of the box on the OpenJFX build --
> maybe because it's a multiproject, or maybe because the jfxrt.jar is not
> created with the jar command?
> I currently do the following: unjar the jfxrt.jar after everything is
> built, apply retrolambda on the class files, and repackage everything.
> Clearly, this is a much dirtier than applying the retrolambda step after
> compilation of the class files in each module.
    defineProperty("JAVAC", cygpath("$JDK_HOME/bin/javac${IS_WINDOWS ? '.exe' : ''}"))
In theory you could make javac be a shell script that would compile the classes then convert them with retolambda. Not sure how easy or hard that would be though, as there is certainly not a 1x1 map to the source files passed to the output classes.

Another likely candidate would be to perform a pass over the class files just before we create the jar. I was just in that code tinkering with the filter mechanism. This would be in:
     def jfxrtTask = task("jfxrt$", type: Jar) {
Not sure how much I like that though, changing all of the class files would mess with timestamps.

The last suggestion - and the one I like best is using the jar closure/action |eachFile <>(action).
It might be possible/reasonable to call retrolambda on each of the class this way, hopefully as a filter so you don't touch the originals.

Based on a change I just sent out for review, I would try to define the action/closure in the platform property file and then conditionally apply it when present.

Here is the example from my review


2777         if (targetProperties.containsKey('jfxrtJarExcludes')) {
2778             exclude(targetProperties.jfxrtJarExcludes)
2779         }

I think the result would be something like:

if (targetProperties.containsKey('jfxrtJarFilter')) {

Then the fun would be constructing the filter to "filter the contents of the file" using retrolambda

> Is there someone with sufficient gradle knowledge who can help here?
> I've watched a number of gradle tutorials, and while I'm more pleased with
> gradle than with maven, the only thing that disturbs me is that
> gradle-professionals claim that "gradle is extremely easy". Build tools are
> NEVER easy for developers :) Some are just a bit easier than others.
> Thanks,
> - Johan

David Hill <David.Hill at>
Java Embedded Development

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