In Java, overloading can occur within a single class or across multiple classes. Method overloading within a single class defining multiple methods in the same class with the same name but different parameter lists. Overloading across multiple classes could occur if multiple classes have methods with the same name but different parameter lists, and the appropriate method is invoked based on the provided arguments and the declared types of the parameters. This allows for flexibility and polymorphism in Java programming. If you have a specific scenario in mind regarding overloading, please feel free to provide more details for a more targeted explanation.

Here's an example of how overloading can be done across multiple classes in Java:

// Superclass
class SuperClass {
    void display(String s) {
        System.out.println("Display method of Superclass with parameter: " + s);
    }
}

// Subclass
class SubClass extends SuperClass {
    // This method is an overload of the display method in the superclass
    void display(int n) {
        System.out.println("Display method of Subclass with parameter: " + n);
    }

    void display(String s, int n) {
        System.out.println("Display method of Subclass with parameters: " + s + ", " + n);
    }
}

// Main Class 
public class MainClass {
    public static void main(String[] args) {
        SubClass obj = new SubClass();
        obj.display(1); // Calls display method in subclass
        obj.display("overload"); // Calls display method in superclass
        obj.display("overload", 2); // Calls display method in subclass
    }
}

This code demonstrates overloading across multiple classes. The SubClass, which extends SuperClass, overloads the display method by having the same name but different parameters. This creates three versions of the display that are correctly called based on the arguments provided.

Both hardware and software firewalls have their own advantages and can play crucial parts in network security. Whether one is 'better' than the other often depends on the specific needs and resources of a particular system or network.

Hardware Firewalls:

1. A hardware firewall sits between the Internet and your network, providing a strong first line of defense against malicious intrusions.
2. It's well-suited for larger networks because it can protect all computers on the network without having to install software on each one.
3. Since a hardware firewall does its processing separately, it could potentially have less impact on system performance.

Software Firewalls:

1. A software firewall runs on your individual computers, providing a more customizable and flexible solution than hardware firewalls.
2. They can control both incoming and outgoing traffic, allowing them to detect and block malicious software programs trying to send information back to a hacker.
3. Software firewalls can be more accessible as many operating systems come with built-in software firewalls.

In an optimal situation, using both hardware and software firewalls offers a layered security approach. The hardware firewall affords broad protection for your network as a whole while the software firewalls provide an additional layer of defense tailored to each individual computer's usage patterns. This combination offers the most comprehensive protection.