[HADOOP-8531] SequenceFile Writer can throw out a better error if a serializer or deserializer isn't available

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.0.2-alpha
• Component/s: io
• Labels: newbie
• Hadoop Flags: Reviewed
• Assignee: madhukara phatak
• Reporter: Harsh J
• Created: 26/Jun/12 18:52
• Updated: 11/Oct/12 17:45
• Resolved: 16/Jul/12 09:03

Description

Currently, if the provided Key/Value class lacks a proper serializer in the loaded config for the SequenceFile.Writer, we get an NPE as the null return goes unchecked.

Hence we get:

java.lang.NullPointerException
	at org.apache.hadoop.io.SequenceFile$Writer.init(SequenceFile.java:1163)
	at org.apache.hadoop.io.SequenceFile$Writer.<init>(SequenceFile.java:1079)
	at org.apache.hadoop.io.SequenceFile$RecordCompressWriter.<init>(SequenceFile.java:1331)
	at org.apache.hadoop.io.SequenceFile.createWriter(SequenceFile.java:271)

We can provide a better message + exception in such cases. This is slightly related to MAPREDUCE-2584.

Issue Links

• relates to: MAPREDUCE-2584 Check for serializers early, and give out more information regarding missing serializers