While emitting a record from my mapper, I am receiving a NullPointerException.
The stack trace seems to indicate there is a problem serializing the Key. The
key contains a few strings and a few longs. It is a string that it is having
trouble serializing. I've checked the contents of the string post-mortem and it
looks like a valid string (at least, other strings like it work just fine).
Could this be a problem not with the string itself but the destination of the
arraycopy()?
The Key.write(DataOutput out) function:
@Override
public void write(DataOutput out) throws IOException {
if(StringOne.equals(null) | StringTwo.equals(null)) {
System.out.println("This is not hit");
}
out.writeUTF(StringOne); //Line 125
out.writeUTF(StringTwo);
out.writeLong(LongOne);
out.writeLong(LongTwo);
}
The Stack Trace:
java.lang.NullPointerException
at java.lang.System.arraycopy(Native Method)
at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer$Buffer.write(MapTask.java:1108)
at java.io.DataOutputStream.write(DataOutputStream.java:90)
at java.io.DataOutputStream.writeUTF(DataOutputStream.java:384)
at java.io.DataOutputStream.writeUTF(DataOutputStream.java:306)
at xxxxxx.xxxxxxxxxxxx.xxxx.xxxxx.xxxxxKey.write(xxxxxKey.java:125)
at
org.apache.hadoop.io.serializer.WritableSerialization$WritableSerializer.serialize(WritableSerialization.java:90)
at
org.apache.hadoop.io.serializer.WritableSerialization$WritableSerializer.serialize(WritableSerialization.java:77)
at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:892)
at
org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:541)
at
org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxxxxx.xxx.xxxxxxxxxxxxxxxxxxxxxxx.map(xxxxxxxxxxxxxxxxxMapper.java:82)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxxxxx.xxx.xxxxxxxxxxxxxxxxxxxxxxx.map(xxxxxxxxxxxxxxxxxMapper.java:63)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxxxx.xxxxxxxxxxxxxxxxxxxxxxxxxxxx.xxxxxxxxxx(xxxxxxxxxxxxxxxxxxxxxxxxxxxx.java:131)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxx.xxxxxxxxxxxxxx.xxxxxxxxxxxxxxx(xxxxxxxxxxxxxx.java:282)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxx.xxxxxxxxxxxxxx.access$000(xxxxxxxxxxxxxx.java:42)
at
xxxxxx.xxxxxxxxxxx.xxxx.xxxxx.xxxxxxxxxxxxxx$xxxxxxxxxxxx.run(xxxxxxxxxxxxx.java:74)
at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
