Final Method Parameters

Question

I've discovered I don't understand final method parameters as I thought I did. The language spec says you can declare a parameter as final, which I would have thought meant the method can't change it. But it turns out the called method can change it. In the following code, the change() method modifies the Test parameter quite easily.
What am I misunderstanding here? If final doesn't keep the parameter from being modified, what does it do?
public class Test
private int privateValue = 0;
* Stores the private value.
* @param privateValue The value to store.
public void setPrivateValue(int value)
   privateValue = value;
public static void change(final Test test)
   test.setPrivateValue(3);
   test.setPrivateValue(4);
* Program entry point
* @param args Command line arguments
public static void main(String[] args)
   Test test = new Test();
   Test.change(test);
   System.out.println("Done");
}

Answer 1

"Ahh, I see," said the blind carpenter, as he picked up his hammer and
saw. I was indeed misunderstanding the use of final. It doesn't protect the
reference object from changes, only the reference variable itself. Sigh...Just to be sure, is this your way of saying "I don't understand those explanations"?
Look closely now :-)
public class Test
private int privateValue = 0;
public void setPrivateValue(int value)
   privateValue = value;
public static void change(final Test test)
   test.setPrivateValue(3); //this line does not even attempt to change the variable's value
   test.setPrivateValue(4); //neither does this one
  //incidentally and irrelevantly, they do ultimately change the value of another variable; a private field of the object pointed to by "test"
   //the next line DOES attempt to change the variable's value
   test = new Test(); //this does not compile because test is declared final
   test = null; //and again!
public static void main(String[] args)
   Test test = new Test();
   Test.change(test);
   System.out.println("Done");
}Variables (and parameters) hold primitives or references (they do not hold objects). For reference variables, they are either null or they point to an object. "final" applies to variables, not to the objects they may point to.
If final
doesn't keep the parameter from being modified, what
does it do?So (I hope) you see, it does just that, generate a compile time error when the parameter is being modified.
What am I misunderstanding here?I don't know. That's exactly what everyone else said.