为什么声明一个函数参数是最终的？

I'm currently working my way through the book "Teach Yourself Android Application Development in 24 Hours" published by Sams. I'm relatively new to Java, Android or otherwise. I have a very solid background in ActionScript 3, which has enough similarities with Java that the language itself isn't hard to grasp, but I do still have some questions about the rationale behind some of the code samples in the book. For example, here's a function that comes with the sample code for Hour 9:I'm currently working my way through the book "