Unable to connect amazon ec2 hadoop instance from outside cluster

Unable to connect amazon ec2 hadoop instance from outside cluster

I have setup amazon ec2 instance and installed hadoop-1.0.4 single node,
started all hadoop components, and working fine.
I tested hadoop cluster by uploading file using hadoop command and working
fine.
When i am accessing hadoop cluster through java code, I am getting
following exception
failed on connection exception: java.net.ConnectException: Connection
refused: no further information
/etc/hosts file
127.0.0.1 localhost
127.0.0.1 ec2-x.x.x.x.compute-1.amazonaws.com ip-x.x.x.x.ec2.internal
core-site.xml
<property>
<name>fs.default.name</name>
<value>hdfs://ec2-x.x.x.x.compute-1.amazonaws.com:54310</value>
</property>
Could you please help me to fix this ?