It should mostly work. I just checked our CHANGES.txt file and haven't seen much incompatibilities introduced between those releases.
But 0.20.3 is pretty old, so only one way to know for sure - compile and run against 1.x.
If you are making that jump, you may as well use the latest releases in 1.x line.
+Vinod Kumar Vavilapalli
On Jun 12, 2013, at 8:34 PM, Lin Yang wrote:
> Hi, all,
> I was wondering could an application written with hadoop 0.20.3 API run on a hadoop 1.0.3 cluster?
> If not, is there any way to run this application on hadoop 1.0.3 instead of re-writing all the code??
> Lin Yang