Thread: Requesting Constructive Criticism About My Code

Hey everybody, after learning most of the basic stuff in java(Strings, Variables, Classes etc...) I really wanted to make a program that would have user input and was also useful. So I made a program that would allow the user to enter a username-password combination and if both entries were correct, it would open up a web page to something really cool, in this case, a picture of bacon. So I would really appreciate if you looked at my code and gave me some tips for future reference.
Here is the code, is there any easier way I could have done this/anything that I missed?

import java.io.IOException;
import javax.swing.JOptionPane;
public class Chuck {
public static void main(String[] args){
 
String username = JOptionPane.showInputDialog("Enter Username");
String password = JOptionPane.showInputDialog("Enter Password");
String user = "bacon123";
String pass = "ilovebacon";	
String url = "https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1024&bih=677&q=bacon&oq=bacon&gs_l=img.3..0l10.4039.4699.0.6159.5.5.0.0.0.0.121.506.2j3.5.0.cpsugrpqhmsignedin%2Chmss2%3Dfalse...0.0..1.1.20.img.ilIvv5MwsRs";
 
{try {
	if (username.equals(user) && password.equals(pass))java.awt.Desktop.getDesktop().browse(java.net.URI.create(url));
	else {JOptionPane.showMessageDialog(null, "Access Denied!", "Error", JOptionPane.ERROR_MESSAGE);}
} 
 
catch (IOException e) {
 
}
}
}
}

Post your code between code tags.

Empty catch blocks are worthless and a bad habit.

To PhHein's point about the length and purpose of the main() method: If you've learned about the use of multiple classes and methods besides the main() method, you should be writing classes and methods with the thought that they might be reusable. Some possibilities here are a class that might be called LoginUser with methods getUserName(), getPassword(), validateUser(), and others as needed. The main() method contained in a separate driver or test class could be used to simply create an instance of LoginUser, possibly passing that instance to a method that tests/exercises every part of the LoginUser class.

Thank you! What do you mean by reusable?

Originally Posted by Wumbo

Thank you! What do you mean by reusable?

Rather than dumping all of the functionality into the main method, the main method should instruct instances to perform actions. For example a simple class used to store two numbers, and has methods to return values based on those numbers. A bank account for example. When you make a deposit, the main method should not say bankAccount.balance += 34;
Rather it should look more like: bankAccount.deposit(34);
With the second version, the deposit method is reusable, and keeps the state modification within the class, as it should be.
Why? Consider another method: bankAccount.withdraw(99999999999);
If the account does not have that amount of cash, the bank can reject the request, or charge a line of credit, or take other actions based on other factors...
Rather if the main method just said bankAccount.balance -= 9999999999; and then spit out the cash at an atm, someone may be upset.
Basically the idea is to encapsulate the functionality of a class within the class, and call on that functionality from outside the class rather than modifying the state of an instance from outside.

Write methods as general as possible. If you write a method called getUserName() so that it includes all possible cases of getting a person's user name with corresponding fault handling, then you should never have to write another method that gets a user's name. The next time you need to get the user's name, you can say, "I already wrote that," and you can REUSE the version you've already written. Maybe it'll need adjusting. Maybe you'll look at it and think, "What was I thinking when I wrote that?" Either way, you'll have a starting point. Eventually, you'll find that the starting point is an acceptable ending point.

Ooooh okay I get it now. Thank you very much for all the help!