public static void main (String [] args) {
     System.out.println("-------- Oracle JDBC Connection Testing ------");

        try {

            Class.forName("oracle.jdbc.driver.OracleDriver");

        } catch (ClassNotFoundException e) {

            System.out.println("Where is your Oracle JDBC Driver?");
            e.printStackTrace();
            return;

        }

        System.out.println("Oracle JDBC Driver Registered!");

        Connection connection = null;
        determineAndSetTnsHome();

        try {

            connection = DriverManager.getConnection(
                    "jdbc:oracle:thin:/@xxx");

        } catch (SQLException e) {

            System.out.println("Connection Failed! Check output console");
            e.printStackTrace();
            return;

        }

        if (connection != null) {
            System.out.println("You made it, take control your database now!");
        } else {
            System.out.println("Failed to make connection!");
        }
    }
private static void determineAndSetTnsHome() {
    String tnsAdmin = System.getenv("TNS_ADMIN");
    if (tnsAdmin == null) {
        String oracleHome = System.getenv("ORACLE_HOME");
        if (oracleHome == null) {
            return; //failed to find any useful env variables
        }
        tnsAdmin = oracleHome + File.separatorChar + "network" + File.separatorChar + "admin";
    }

    System.setProperty("oracle.net.tns_admin", tnsAdmin);
}