Re: Getting this exception "java.net.ConnectException: Call From ubuntu/127.0.0.1 to ubuntu:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused"

When trying to run the job I am getting this exception. I am using
Apache Hadoop 1.1.1 version. I could see all the services started
successfully.

Can some one please help me.

My entries in the /etc/hosts file are:

************************************************
127.0.0.1 localhost
127.0.0.1 ubuntu

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
****************************************************************
********************

hduser@ubuntu:~/hadoop111/bin$ hadoop jar ../hadoop-examples-1.1.1.jar
pi 3 10
Number of Maps = 3
Samples per Map = 10
java.net.ConnectException: Call From ubuntu/127.0.0.1 to ubuntu:8020
failed on connection exception: java.net.ConnectException: Connection
refused; For more details see: http://wiki.apache.org/hadoop/**
ConnectionRefused <http://wiki.apache.org/hadoop/ConnectionRefused>
at sun.reflect.**NativeConstructorAccessorImpl.**newInstance0(Native
Method)
at sun.reflect.**NativeConstructorAccessorImpl.**newInstance(**
NativeConstructorAccessorImpl.**java:39)
at sun.reflect.**DelegatingConstructorAccessorI**mpl.newInstance(**
DelegatingConstructorAccessorI**mpl.java:27)
at java.lang.reflect.Constructor.**newInstance(Constructor.java:**
513)
at org.apache.hadoop.net.**NetUtils.wrapWithMessage(**
NetUtils.java:779)
at org.apache.hadoop.net.**NetUtils.wrapException(**
NetUtils.java:726)
at org.apache.hadoop.ipc.Client.**call(Client.java:1229)
at org.apache.hadoop.ipc.**ProtobufRpcEngine$Invoker.**
invoke(ProtobufRpcEngine.java:**202)
at $Proxy9.getFileInfo(Unknown Source)
at sun.reflect.**NativeMethodAccessorImpl.**invoke0(Native Method)
at sun.reflect.**NativeMethodAccessorImpl.**invoke(**
NativeMethodAccessorImpl.java:**39)
at sun.reflect.**DelegatingMethodAccessorImpl.**invoke(**
DelegatingMethodAccessorImpl.**java:25)
at java.lang.reflect.Method.**invoke(Method.java:597)
at org.apache.hadoop.io.retry.**RetryInvocationHandler.**
invokeMethod(**RetryInvocationHandler.java:**164)
at org.apache.hadoop.io.retry.**RetryInvocationHandler.invoke(**
RetryInvocationHandler.java:**83)
at $Proxy9.getFileInfo(Unknown Source)
at org.apache.hadoop.hdfs.**protocolPB.**
ClientNamenodeProtocolTranslat**orPB.getFileInfo(**
ClientNamenodeProtocolTranslat**orPB.java:628)
at org.apache.hadoop.hdfs.**DFSClient.getFileInfo(**
DFSClient.java:1545)
at org.apache.hadoop.hdfs.**DistributedFileSystem.**getFileStatus(**
DistributedFileSystem.java:**805)
at org.apache.hadoop.fs.**FileSystem.exists(FileSystem.**java:1367)
at org.apache.hadoop.examples.**PiEstimator.estimate(**
PiEstimator.java:269)
at org.apache.hadoop.examples.**PiEstimator.run(PiEstimator.**
java:342)
at org.apache.hadoop.util.**ToolRunner.run(ToolRunner.**java:70)
at org.apache.hadoop.examples.**PiEstimator.main(PiEstimator.**
java:351)
at sun.reflect.**NativeMethodAccessorImpl.**invoke0(Native Method)
at sun.reflect.**NativeMethodAccessorImpl.**invoke(**
NativeMethodAccessorImpl.java:**39)
at sun.reflect.**DelegatingMethodAccessorImpl.**invoke(**
DelegatingMethodAccessorImpl.**java:25)
at java.lang.reflect.Method.**invoke(Method.java:597)
at org.apache.hadoop.util.**ProgramDriver$**
ProgramDescription.invoke(**ProgramDriver.java:72)
at org.apache.hadoop.util.**ProgramDriver.driver(**
ProgramDriver.java:144)
at org.apache.hadoop.examples.**ExampleDriver.main(**
ExampleDriver.java:64)
at sun.reflect.**NativeMethodAccessorImpl.**invoke0(Native Method)
at sun.reflect.**NativeMethodAccessorImpl.**invoke(**
NativeMethodAccessorImpl.java:**39)
at sun.reflect.**DelegatingMethodAccessorImpl.**invoke(**
DelegatingMethodAccessorImpl.**java:25)
at java.lang.reflect.Method.**invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.**main(RunJar.java:208)
Caused by: java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.**checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.**finishConnect(**
SocketChannelImpl.java:567)
at org.apache.hadoop.net.**SocketIOWithTimeout.connect(**
SocketIOWithTimeout.java:207)
at org.apache.hadoop.net.**NetUtils.connect(NetUtils.**java:525)
at org.apache.hadoop.net.**NetUtils.connect(NetUtils.**java:489)
at org.apache.hadoop.ipc.Client$**Connection.setupConnection(**
Client.java:499)
at org.apache.hadoop.ipc.Client$**Connection.setupIOstreams(**
Client.java:593)
at org.apache.hadoop.ipc.Client$**Connection.access$2000(Client.**
java:241)
at org.apache.hadoop.ipc.Client.**getConnection(Client.java:**1278)
at org.apache.hadoop.ipc.Client.**call(Client.java:1196)
... 29 more
hduser@ubuntu:~/hadoop111/bin$