Hi, experts.
I wrote a spark program to write a sequence file. I found if I used the
NullWritable as the Key Class of the SequenceFile, the program reported
exceptions. But if I used the BytesWritable or Text as the Key Class, the
program did not report the exceptions.
Does spark not support NullWritable class? The spark version I use is 1.3.0
and the exceptions are as following:
ERROR yarn.ApplicationMaster: User class threw exception:
scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
java.lang.NoSuchMethodError:
scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
at dhao.test.SeqFile.TestWriteSeqFile02$.main(TestWriteSeqFile02.scala:21)
at dhao.test.SeqFile.TestWriteSeqFile02.main(TestWriteSeqFile02.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at
org.apache.spark.deploy.yarn.ApplicationMaster$$anon$2.run(ApplicationMaster.scala:480)
