ExecutorServiceの拡張がうまくできん -> メソッド名のせいかな？

executor_submit3.groovy

import java.util.concurrent.ExecutorService
import java.util.concurrent.BlockingQueue
import java.util.concurrent.LinkedBlockingQueue
import java.util.concurrent.Executors
import java.util.concurrent.Callable

def executor = Executors.newSingleThreadExecutor()
// Closure as Interfaceパターン！
def future = executor.submit( {
  def list = []
    (1..10).each {
      println "in Callable ${it}"
      list << it
  }
  return list
} as Callable )
println "result get -> ${future.get()}"

console2.log

in Callable 1
in Callable 2
in Callable 3
in Callable 4
in Callable 5
in Callable 6
in Callable 7
in Callable 8
in Callable 9
in Callable 10
result get -> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

executor_submit2.groovy

import java.util.concurrent.ExecutorService
import java.util.concurrent.BlockingQueue
import java.util.concurrent.LinkedBlockingQueue
import java.util.concurrent.Executors
import java.util.concurrent.Callable

ExecutorService.metaClass.define {
    //submit = {Closure closure ->
    submit2 = {Closure closure ->
        return delegate.submit (new Callable(){
            @Override
            Object call() {
                return closure()
            }
        })
    }
}

def executor = Executors.newSingleThreadExecutor()
//def future = executor.submit {
def future = executor.submit2 {
    def list = []
    (1..10).each {
        println "in Callable ${it}"
        list << it
    }
    return list
}
println "result get -> ${future.get()}"