Missing method error in Gradle 2.14-rc-5 on Windows

build.gradle

import java.nio.file.Paths
import java.nio.file.Files

apply plugin: 'cpp'

model {
    repositories {
        libs(PrebuiltLibraries) {
            jvm {
                def path = findJdkIncludePath()?.toString()
                if(path == null) {
                    def msg = "Could not find JDK include directory."
                    throw new ProjectConfigurationException(msg, null)
                }
                headers.srcDirs path, "$path/win32", "$path/linux", "$path/darwin"
            }
        }
    }
    
    components {
        main(NativeLibrarySpec) {
            sources {
                cpp.lib library: "jvm", linkage: "api"
            }
        }
    }
}

def findJdkIncludePath() {
    def home = System.properties['user.home']
    def path = Paths.get(home, ".java_home", "include")
    if(Files.exists(path.resolve("jni.h"))) {
        return path
    }
    
    def os = System.properties['os.name'].toLowerCase()
    if(os.contains("win")) {
        def programFilesJava = Paths.get(System.env['PROGRAMFILES'], "Java")
        def javaVersion = System.properties['java.version']
        return programFilesJava.resolve("jdk${javaVersion}", "include")
        
    } else if(os.contains("nix") || os.contains("nux")) {
        return Paths.get(System.properties['java.home'], "..", "include")
    }
    return null
}

// Alternate version that produces no error
/*
def findJdkIncludePath() {
    def home = System.properties['user.home']
    return Paths.get(home, ".java_home", "include")
}
*/