I am trying to send a few ping requests and want to handle the pong replies. What is the best way to go about it?

I tried extending StandardMessageRouter class and overriding handlePingRequestForMe method. I initialized the required classes like acceptor FileManager, Authenticator .... etc in a main method but got the following exception:

java.lang.NullPointerException
at com.sun.java.util.collections.Arrays.sort(Arrays.j ava:1102)
at com.limegroup.gnutella.FileManager.loadSettingsBlo cking(FileManager.j
ava:472)
at com.limegroup.gnutella.FileManager$1.run(FileManag er.java:416)
java.io.IOException
at com.limegroup.gnutella.util.SocketOpener.connect(S ockets.java:183)
at com.limegroup.gnutella.util.Sockets.connect(Socket s.java:105)
at com.limegroup.gnutella.Connection.initializeWithou tRetry(Connection.j
ava:253)
at com.limegroup.gnutella.Connection.initialize(Conne ction.java:213)
at com.limegroup.gnutella.ManagedConnection.initializ e(ManagedConnection
.java:349)
at com.limegroup.gnutella.ConnectionManager.initializ eExternallyGenerate
dConnection(ConnectionManager.java:1225)
at com.limegroup.gnutella.ConnectionManager.createCon nectionBlocking(Con
nectionManager.java:173)
at myStart.main(myStart.java:29)
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Thanks in advance for any help

Sriram