conf.Configuration: java.io.IOException: config(config)

[Sonal Goyal]

Hi,

I am running Hadoop standalone to test some functionality. I have set the
log level to DEBUG and I see the following exception:

DEBUG conf.Configuration: java.io.IOException: config(config)
    at org.apache.hadoop.conf.Configuration.<init>(Configuration.java:225)
    at org.apache.hadoop.mapred.JobConf.<init>(JobConf.java:183)
    at org.apache.hadoop.mapreduce.JobContext.<init>(JobContext.java:52)
    at
org.apache.hadoop.mapreduce.TaskAttemptContext.<init>(TaskAttemptContext.java:35)
    at
org.apache.hadoop.mapreduce.TaskInputOutputContext.<init>(TaskInputOutputContext.java:44)
    at
org.apache.hadoop.mapreduce.ReduceContext.<init>(ReduceContext.java:68)
    at org.apache.hadoop.mapreduce.Reducer$Context.<init>(Reducer.java:132)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.apache.hadoop.mapred.Task.createReduceContext(Task.java:1053)
    at
org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:558)
    at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:408)
    at
org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:215)

I checked the source, and I see the org.apache.hadoop.conf.Configuration
file has code:

 if (LOG.isDebugEnabled()) {
      LOG.debug(StringUtils.stringifyException
                (new IOException("config(config)")));
    }

I am bafflled by this block of code. Why is an IOException being thrown if
the log level is set to DEBUG ? It would be great if someone could shed some
light on this.

Thanks,
Sonal