public class xx{

  public int fieldsX = 4;//inputInt 成员变量完全没问题
  public static int fieldsX2 = 4;//需要同步

  public Factory fieldsF = new Factory();//fieldsF 成员变量完全没问题
  public static Factory fieldsF2;//需要同步

  static{
    fieldsF2 = new Factory();
  }


  public Factory yy(Factory inputFactory，int inputInt){
  //inputInt 原始型变量完全没问题, 
  //inputFactory 怎么说呢，传的是引用，
  //如果改变它(inputFactory)的成员变量 需要同步，否则就不用了
    int intLocal = 3;//完全没问题
    Factory factoryLocal;
    if(){
      factoryLocal = new Factory();
        factoryLocal.mm = 23;//完全没问题
      return factoryLocal;
    }
    else{
      factoryLocal = inputFactory;
      synchronized(factoryLocal){
        factoryLocal.mm = 23;//需要同步
      }
      return factoryLocal;
    }
  }

}