String  IP = "Server99";
String  port = "1521";
String  DBNAME= "PGDB";
String  mcS_UserName="UserName";
String  mcS_Password="Password";
String JDBC_DRIVER="oracle.jdbc.driver.OracleDriver";
Connection conn;
String DB_URL= "jdbc:oracle:thin:@"+IP+":"+port+":"+DBNAME;
Class.forName(JDBC_DRIVER);
conn = DriverManager.getConnection(DB_URL,mcS_UserName,mcS_Password);

]$ tnsping Server099

TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 01-MAR-2016  14:02:54

Copyright (c) 1997, 2009, Oracle.  All rights reserved.

Used parameter files:
/home/oracle/app/oracle/product/11.2.0/dbhome_1/network/admin/sqlnet.ora

Used EZCONNECT adapter to resolve the alias
Attempting to contact (DESCRIPTION=(CONNECT_DATA=(SERVICE_NAME=))(ADDRESS=  (PROTOCOL=TCP)(HOST=127.0.0.1)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(HOST=10.0.0.99)(PORT=1521)))