Java 1.5里面是这么说的：（http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Deprecated.html） A program element annotated @Deprecated is one that programmers are discouraged from using, typically because it is dangerous, or because a better alternative exists. Compilers warn when a deprecated program element is used or overridden in non-deprecated code.如果是Bug呢？换一个方法写，然后把原来的加个Deprecated就好了？
保持对以前该API的client的兼容性
A program element annotated @Deprecated is one that programmers are discouraged from using, typically because it is dangerous, or because a better alternative exists. Compilers warn when a deprecated program element is used or overridden in non-deprecated code.如果是Bug呢？换一个方法写，然后把原来的加个Deprecated就好了？