pass parameter "a" to class java for the command line argument

public static void main(String[] args)
{

        for (String a : args) {

        System.out.println(a);
    }

public class CustomConfiguration {

public static void readConfig(String filename) {
//read from config.properties file

try {

        String File = filename;
        System.out.println ("ConfigFile :" + File);
String result = "";
Properties properties = new Properties();
String propFileName = filename;
InputStream inputStream = new FileInputStream(propFileName);
    }

}

My question is how can i pass the "a" to the CustomConfiguration class?