1 package org.apache.hadoop.classification; 2  3 import java.lang.annotation.Documented; 4  5 /** 6  * Annotation to inform users of how much to rely on a particular package, 7  * class or method not changing over time. 8  */ 9  //说明被他们注解的类型的稳定性10 @InterfaceAudience.Public11 @InterfaceStability.Evolving12 public class InterfaceStability {13   /**14    * Can evolve while retaining compatibility for minor release boundaries.; 15    * can break compatibility only at major release (ie. at m.0).16    */17   @Documented18   public @interface Stable {};19   //主版本是稳定的，不同主版本间可能不兼容20   /**21    * Evolving, but can break compatibility at minor release (i.e. m.x)22    */23   @Documented24   public @interface Evolving {};25   //不断变化，不同次版本间可能不兼容26   /**27    * No guarantee is provided as to reliability or stability across any28    * level of release granularity.29    */30   @Documented31   public @interface Unstable {};32   //没有任何可靠性和健壮性保证33 }