Filled originally as:
https://netbeans.org/bugzilla/show_bug.cgi?id=237070

javac accepts (produces classfile for):
----
public class C {
    void m(void v) {}
}
----

Attempts to run/load than classfile lead to:
Exception in thread "main" java.lang.ClassFormatError: Method "m" in class C has illegal signature "(V)V"

Reproducible with:
$ javac -fullversion
javac full version "1.7.0-b147"
and with:
$ javac -fullversion
javac full version "1.7.0_05-b06"

But not with (this version correctly produces compile-time errors):
$ javac -fullversion
javac full version "1.6.0_38-b05"