NullPointerException when trying to create a new PigServer

[Vincent Barat]

Hello,

From time to time, my analytics program (which creates and use 
internally several pig servers) triggers a NullPointerException 
during PigServer initialization.

Any idea about what could be the cause of the issue ?

Here is the stack trace (PIG 0.6.0):

> handler: thread Sessions (79) exiting due to uncaught exception
> java.lang.NullPointerException
>          at java.util.Hashtable.put(Hashtable.java:394)
>          at java.util.Properties.setProperty(Properties.java:143)
>          at 
org.apache.hadoop.conf.Configuration.set(Configuration.java:446)
>          at 
org.apache.pig.backend.hadoop.datastorage.ConfigurationUtil.toConfiguration(ConfigurationUtil.java:37)
>          at 
org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.init(HExecutionEngine.java:169)
>          at 
org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.init(HExecutionEngine.java:136)
>          at 
org.apache.pig.impl.PigContext.connect(PigContext.java:201)
>          at org.apache.pig.PigServer.<init>(PigServer.java:169)
>          at org.apache.pig.PigServer.<init>(PigServer.java:158)
>          at 
com.ubikod.ermin.analytics.Analytics.getNewPigServer(Analytics.java:110)
>          at 
com.ubikod.ermin.analytics.stats.Stat.prepare(Stat.java:43)
>          at 
com.ubikod.ermin.analytics.stats.SessionStat.prepare(SessionStat.java:21)
>          at 
com.ubikod.ermin.analytics.stats.Stat.compute(Stat.java:79)
>          at 
com.ubikod.ermin.analytics.stats.AllStats$1.run(AllStats.java:137)
> 2010-03-17 00:47:22,268 | FATAL | Crashes | Main       | Uncaught
> handler: thread Crashes (84) exiting due to uncaught exception
> java.lang.IllegalStateException: Shutdown in progress
>          at 
java.lang.ApplicationShutdownHooks.add(ApplicationShutdownHooks.java:39)
>          at java.lang.Runtime.addShutdownHook(Runtime.java:192)
>          at 
org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:1478)
>          at 
org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1464)
>          at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:197)
>          at 
org.apache.pig.backend.hadoop.datastorage.HDataStorage.init(HDataStorage.java:70)
>          at 
org.apache.pig.backend.hadoop.datastorage.HDataStorage.<init>(HDataStorage.java:53)
>          at 
org.apache.pig.impl.PigContext.connect(PigContext.java:205)
>          at org.apache.pig.PigServer.<init>(PigServer.java:169)
>          at org.apache.pig.PigServer.<init>(PigServer.java:158)
>          at 
com.ubikod.ermin.analytics.Analytics.getNewPigServer(Analytics.java:110)
>          at 
com.ubikod.ermin.analytics.stats.Stat.prepare(Stat.java:43)
>          at 
com.ubikod.ermin.analytics.stats.CrashStat.prepare(CrashStat.java:16)
>          at 
com.ubikod.ermin.analytics.stats.Stat.compute(Stat.java:79)
>          at 
com.ubikod.ermin.analytics.stats.AllStats$1.run(AllStats.java:137)