package scalapackageimport scala.collection.mutable.ArrayBuffer/**  * Created by Germmy on 2018/3/20.  */object SingletonObject {  def main(args: Array[String]) {    println(SessionFactory.getSessions)    println(SessionFactory.getSessions.size)    println(SessionFactory.getSessions(0))    println(SessionFactory.removeSession)  }}object SessionFactory {  println("SessionFactory 被执行了")  var i = 5  val sessions = new ArrayBuffer[Session]()  while (i > 0) {    sessions += new Session //不确定这样写行不行    i -= 1  }  def getSessions: ArrayBuffer[Session] = sessions  def getSessionsNew = sessions //简写也要写=  def addSession: Unit = {    sessions += new Session  }  def removeSession: Unit = {    sessions.remove(0)  }}class Session {}