I am talking about languages which can crosscompile with Java source-code level. So class in Scala can be extended by Java class and again extended by Scala class and so on... By my knowledge this is AspectJ, Kotlin, Scala, Groovy and probably Ceylon
This requires deep integration with Java Development Tools to make incremental compilation working. And JDT team refuses this sort of stuff for nearly a decade now (since AspectJ). There are various hacks (such as aspect hooks used by Scala IDE). Probably best solution is JDT fork made by Spring Source (VMware) :
http://blog.springsource.org/2009/07/30/a-groovier-eclipse-e...
And to add insult to injury Eclipse Foundation created their own language called Xtend. It has cross-compilation as well, but it first compiles down to Java source code and result Java code is than compiled by javac. Basically Java Preprocessor. (dont get me wrong. I really like Xtend as language, I just wish their team would put some pressure on JDT folks).
This requires deep integration with Java Development Tools to make incremental compilation working. And JDT team refuses this sort of stuff for nearly a decade now (since AspectJ). There are various hacks (such as aspect hooks used by Scala IDE). Probably best solution is JDT fork made by Spring Source (VMware) : http://blog.springsource.org/2009/07/30/a-groovier-eclipse-e...
And to add insult to injury Eclipse Foundation created their own language called Xtend. It has cross-compilation as well, but it first compiles down to Java source code and result Java code is than compiled by javac. Basically Java Preprocessor. (dont get me wrong. I really like Xtend as language, I just wish their team would put some pressure on JDT folks).