As the majority of the GUI interface is handled by JGoodies Forms (http://www.jgoodies.com/index.html), the PasswordPress jar file is only 7kb, making it ideal to add to your projects where you might need to have a randomly generated key or password.
Depending on the options you select, UnearthedPassword can handle passwords/keys up to the limits of an int (if you allow duplicate characters in the result).
You can utilize the example contained in the file Test.java to see how to integrate UnearthedPassword into your applications.
There are constants embedded in UnearthedPassword to help:
UnearthedPassword .IS_NUMERIC for numeric only passwords
UnearthedPassword .IS_ALPHA for alphabetic only passwords
UnearthedPassword .IS_ALPHANUM for alphanumeric passwords
I hope you enjoy UnearthedPassword and PasswordPress.