public OrderedThreadPoolExecutor(){
  this(DEFAULT_INITIAL_THREAD_POOL_SIZE,DEFAULT_MAX_THREAD_POOL,DEFAULT_KEEP_ALIVE,TimeUnit.SECONDS,Executors.defaultThreadFactory(),null);
}

public OrderedThreadPoolExecutor ( ) { this ( DEFAULT_INITIAL_THREAD_POOL_SIZE , DEFAULT_MAX_THREAD_POOL , DEFAULT_KEEP_ALIVE , TimeUnit . SECONDS , Executors . defaultThreadFactory ( ) , null ) ; }
creates a default threadpool , with default values : - minimum pool size is 0 - maximum pool size is 16 - keepalive set to 30 seconds - a default threadfactory - all events are accepted
