Merge -r 765958:765959 from trunk to 0.20 to fix HADOOP-5691.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.20@765960 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -878,6 +878,10 @@ Release 0.20.0 - 2009-04-15
     HADOOP-5646. Fixes a problem in TestQueueCapacities. 
     (Vinod Kumar Vavilapalli via ddas)
 
+    HADOOP-5691. Makes org.apache.hadoop.mapreduce.Reducer concrete class 
+    instead of abstract. (Amareshwari Sriramadasu via sharad)
+
+
 Release 0.19.2 - Unreleased
 
   BUG FIXES

src/mapred/org/apache/hadoop/mapreduce/Reducer.java

@@ -115,7 +115,7 @@ import org.apache.hadoop.mapred.RawKeyValueIterator;
  * @see Mapper
  * @see Partitioner
  */
-public abstract class Reducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {
+public class Reducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {
 
   public class Context 
     extends ReduceContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {