Runping,
AggregatorTests is actually used by the unit test class TestAggregates.java which is in test/org/apache/hadoop/mapred. Not sure why I put TestAggregates in that dir though. I can move the code easily if it is desired to do so.
I missed TestAggregates. I think it belongs better with AggregatorTests, so yes I would suggest it's moved to org.apache.hadoop.mapred.lib.aggregate.
As to the abacus example code, the code itself is a bit weird --- it is generated by Jython. I was not happy with it. And I did not have time to write a nicer example. Now that release 0.13 is out, I'll find some time to write an example.
The code in src/contrib/abacus/src/examples is generated with Jython? It looks OK to me. Whatever, I've created a Jira issue to sort out the examples (https://issues.apache.org/jira/browse/HADOOP-1547).
If you open Jiras for those issues, I or somebody in my team will pick them up.
Thanks! Tom
