Can you try adding 'org.apache.hadoop.io.serializer.JavaSerialization,' to the following config ? "C:\hadoop-0.20.2\src\core\core-default.xml"(87,9): <name>io.serializations</name>
By default, only org.apache.hadoop.io.serializer.WritableSerialization is included. On Tue, Apr 27, 2010 at 3:55 PM, Farhan Husain <farhan.hus...@csebuet.org>wrote: > I tried to use a class which implements the Serializable interface and got > the following error: > > java.lang.NullPointerException > at > > org.apache.hadoop.io.serializer.SerializationFactory.getSerializer(SerializationFactory.java:73) > at > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:759) > at > > org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:487) > at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:575) > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305) > at org.apache.hadoop.mapred.Child.main(Child.java:170) > > On Tue, Apr 27, 2010 at 12:53 PM, Farhan Husain > <farhan.hus...@csebuet.org>wrote: > > > Hello, > > > > I want to output a class which I have written as the value of the map > > phase. The obvious was is to implement the Writable interface but the > > problem is the class has other classes as its member properties. The > > DataInput and DataOutput interfaces used by the read and write methods of > > the Writable class do not support object serialization. Is there any > other > > way I can achieve this? > > > > Thanks, > > Farhan > > >
