Kindly paste your asterisk log while executing your java program
For getting asterisk log
tail -f /var/log/asterisk/full
For checking the same from command line try this
telnet 192.168.68.173 5038
Action: Login
Username: admin
Secret: admin
if login sucessfull
Action: Originate
Channel: SIP/1010
Exten: 2020
Context: default
Priority: 1
Callerid: 1010
Async: yes
Try this and let me know your outputs