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Hui Wen Han commented on MAHOUT-353: ------------------------------------ I run a few times ,get following error: java.lang.NullPointerException at org.apache.mahout.cf.taste.impl.common.FastMap.put(FastMap.java:178) at org.apache.mahout.cf.taste.impl.common.Cache.getAndCacheValue(Cache.java:127) at org.apache.mahout.cf.taste.impl.common.Cache.get(Cache.java:94) at org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper.map(RecommenderMapper.java:111) at org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper.map(RecommenderMapper.java:52) at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50) at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:358) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307) at org.apache.hadoop.mapred.Child.main(Child.java:170) > java.lang.NullPointerException in RecommenderMapper > --------------------------------------------------- > > Key: MAHOUT-353 > URL: https://issues.apache.org/jira/browse/MAHOUT-353 > Project: Mahout > Issue Type: Bug > Components: Collaborative Filtering > Affects Versions: 0.4 > Reporter: Hui Wen Han > Fix For: 0.4 > > > java.lang.NullPointerException > at > org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper$CooccurrenceCache.get(RecommenderMapper.java:169) > at > org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper$CooccurrenceCache.get(RecommenderMapper.java:154) > at > org.apache.mahout.cf.taste.impl.common.Cache.getAndCacheValue(Cache.java:125) > at org.apache.mahout.cf.taste.impl.common.Cache.get(Cache.java:94) > at > org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper.map(RecommenderMapper.java:111) > at > org.apache.mahout.cf.taste.hadoop.item.RecommenderMapper.map(RecommenderMapper.java:52) > at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50) > at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:358) > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307) > at org.apache.hadoop.mapred.Child.main(Child.java:170) -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.