辛格尔顿：什么是更好的选择？

Question

方法1

 public static synchronized Database getInstance(){
   if(INSTANCE == null){
     INSTANCE = new Database();
   }
   return INSTANCE;
}

方法2

private static final Database INSTANCE = new Database();
    public static Database getInstance(){
        return INSTANCE;
    }

哪个是更好的选择？