m_1988的专栏

----------------------------------------------公共的抽象父类或接口-------------------------------- public abstract class Car {      public abstract void start(); }   ---------------------------------------

----------------------------------------------公共的抽象父类或接口-------------------------------- public abstract class Car {      public abstract void start(); }   ---------------------------------------

----------------------------------------------类------------------------------------------------   public class MySingLeton {  /**   * 一个静态变量指向自己   */  private static MySingLeton instance = null;