Scala is not mature enough for Weld

Scala is not mature enough for Weld (or any other reflection related operation). Turns out that one of the feature that make Scala so interesting (closures) is also a source of incompatibility (the internal anonymous class files that generate are invalid)

So, if for example, I have a code like this (inside any method in a class):

val classNames = Conversions.convertList(names).reduceLeft[String] { (acc, n) =>
       acc + ", " + n
}

That generates an inner class that makes Java reflection unusable:

java.lang.IncompatibleClassChangeError: com.googlecode.solder.dwr.WeldContainer and com.googlecode.solder.dwr.WeldContainer$$anonfun$getClasses$1 disagree on InnerClasses attribute
 at java.lang.Class.getDeclaringClass(Native Method)
 at java.lang.Class.getEnclosingClass(Class.java:1085)
 at java.lang.Class.getSimpleBinaryName(Class.java:1220)
 at java.lang.Class.getSimpleName(Class.java:1112)
 at org.jboss.weld.util.Names.typeToString(Names.java:251)
 at org.jboss.weld.util.Names.classToString(Names.java:263)
 at org.jboss.weld.introspector.jlr.WeldClassImpl.<init>(WeldClassImpl.java:151)
 at org.jboss.weld.introspector.jlr.WeldClassImpl.of(WeldClassImpl.java:133)
 at org.jboss.weld.resources.ClassTransformer$2.call(ClassTransformer.java:72)
 at org.jboss.weld.resources.ClassTransformer$2.call(ClassTransformer.java:68)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at org.jboss.weld.util.collections.ConcurrentCache.putIfAbsent(ConcurrentCache.java:125)
 at org.jboss.weld.resources.ClassTransformer.loadClass(ClassTransformer.java:67)
 at org.jboss.weld.bootstrap.BeanDeployer.addClass(BeanDeployer.java:59)
 at org.jboss.weld.bootstrap.BeanDeployer.addClasses(BeanDeployer.java:86)
 at org.jboss.weld.bootstrap.BeanDeployment.deployBeans(BeanDeployment.java:134)
 at org.jboss.weld.bootstrap.WeldBootstrap.deployBeans(WeldBootstrap.java:367)
 at org.jboss.weld.environment.servlet.Listener.contextInitialized(Listener.java:158)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3843)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4342)
 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
 at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
 at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
 at org.apache.catalina.core.StandardService.start(StandardService.java:516)
 at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
 at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
 at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)

Apparently this is a known problem since 2008-08-03 (16 months so far) and AFAIK they are not in a hurry to fix it.

I guess that means I am going to have to start removing Scala from my Weld project. I am sad about this because Scala is IMO a really beautiful language, that feels much cleaner than Java, but if the .class files that it generates are not compatible with the rest of Java... it is just useless for me.

Playing with Weld and Scala to create a new framework for JSPs

Today I built my first "serious" example using Weld and Scala.
You can take a look at it in here.
So far, Weld looks like really good framework, I am still not able to say that it will replace Spring as my "glue framework", but that could certainly become true.
Scala also looks interesting (this also my first "serious" attempt at doing something with Scala), but the support for Scala in Eclipse is very fragile... the plug-in still needs a lot of polishing (no refatoring, no quickfixes, and the syntax coloring and cursor control sometimes goes crazy). I would not recommend the Scala plugin in Eclipse for "real work", but for hobbing is fine. (I wonder if the support for Scala in the Netbeans or the opensourced version of IntelliJ is better).