check whether internet connection available or not

netavail

/**
 *Check internet connectivity by ping
 */
public Boolean isOnline() {
    try {
        p1 = java.lang.Runtime.getRuntime().exec("ping -c 1 www.google.com");
        int returnVal = p1.waitFor();
        boolean reachable = (returnVal == 0);
        if (reachable) {

            System.out.println("Internet access");
            return reachable;
        } else {

            System.out.println("No Internet access");
        }

    } catch (Exception e) {

        e.printStackTrace();
    } finally {
        p1.destroy();
    }
    return false;
}