class Config {
    //type constant
    static final int maxConnections = 3;

    //type fields
    static public String host;
    static public int port;

    //type method
    static public String GetConnection() {
        return String.format("%s:%s", host, port);
    }

    //type initializer
    static {
        host = "10.0.0.1";
    }
}

Config.port = 52;
var connection = Config.GetConnection();
//connection is "10.0.0.1:52"
System.out.println(connection);

Config.host = "10.0.0.3";
connection = Config.GetConnection();
//connection is "10.0.0.3:52"  
System.out.println(connection);