when i compile android2.1 source,it give me a attention:android some files use or override a deprecated api,Please use - Xlink: deprecation recompiled. can you tell me why give us this information,it It will have a negative effect ?
It will not have any negative effect or anything for you to worry about.
It's because the Android sourcecode (in Java) is written for compatibility with older JDK versions (like 1.4, 1.5). And in recent versions some of the old APIs had been deprecated.