Gradle's War task has methods for working with the WEB-INF CopySpec:
getWebInf()
webInf(Action<CopySpec>)
webInf(Closure)
BootJar has no such methods for its CopySpec for BOOT-INF which is analogous to the War task's CopySpec for WEB-INF. When should add both getWebInf() and webInf(Action<CopySpec>). I don't think there's any need for webInf(Closure) as Groovy can happily use the Action variant.