Connection could not be allocated because: Io exception: Connection refused(DESCRIPTION=(ERR=1153)(VSNNUM=169870336)(ERROR_STACK=(ERROR=(CODE=1153)(EMFI=4)(ARGS='(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=oxxxxx(PORT=1521))(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))null))'))(ERROR=(CODE=303)(EMFI=1))))

Nov 14, 2011 11:29:02 AM com.sun.enterprise.resource.LocalTxConnectorAllocator createResource

WARNING: RAR5038:Unexpected exception while creating resource for pool jdbc/xxx/xxx_ds. Exception : Connection could not be allocated because: Io exception: Connection refused(DESCRIPTION=(ERR=1153)(VSNNUM=169870336)(ERROR_STACK=(ERROR=(CODE=1153)(EMFI=4)(ARGS='(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=ora-xxx.com)(PORT=1521))(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))null))'))(ERROR=(CODE=303)(EMFI=1))))

Nov 14, 2011 11:29:02 AM com.sun.enterprise.resource.AbstractResourcePool resizePool

WARNING: RAR5058: Error while Resizing pool jdbc/xx/xx_ds. Exception : Connection could not be allocated because: Io exception: Connection refused(DESCRIPTION=(ERR=1153)(VSNNUM=169870336)(ERROR_STACK=(ERROR=(CODE=1153)(EMFI=4)(ARGS='(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=ora-xxxx.com)(PORT=1521))(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))null))'))(ERROR=(CODE=303)(EMFI=1))))

Nov 14, 2011 11:34:13 AM com.sun.enterprise.resource.LocalTxConnectorAllocator createResource

WARNING: RAR5038:Unexpected exception while creating resource for pool jdbc/xxx_ds. Exception : Connection could not be allocated because: Io exception: Connection refused(DESCRIPTION=(ERR=1153)(VSNNUM=169870336)(ERROR_STACK=(ERROR=(CODE=1153)(EMFI=4)(ARGS='(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=ora-xxx.com)(PORT=1521))(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))null))'))(ERROR=(CODE=303)(EMFI=1))))

Nov 14, 2011 11:34:13 AM com.sun.enterprise.resource.AbstractResourcePool resizePool

WARNING: RAR5058: Error while Resizing pool jdbc/xxx_ds. Exception : Connection could not be allocated because: Io exception: Connection refused(DESCRIPTION=(ERR=1153)(VSNNUM=169870336)(ERROR_STACK=(ERROR=(CODE=1153)(EMFI=4)(ARGS='(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xxx.com)(PORT=1521))(CONNECT_DATA=(CID=(PROGRAM=)(HOST=__jdbc__)(USER=))null))'))(ERROR=(CODE=303)(EMFI=1))))

If we get like this error we need to use ojdbc6.jar for java code compilation