Related with Final Keyword...

Question

Hi,
I written the following code to iterate over an array :
for(final int i:arr)
System.out.println(i);
}

Answer 1

jschell wrote:
I really doubt that the compiler doesn't erase the final part.
It is a compile time rather than run time check.Runtime as well, it seems.
public class Final {
  public static final int i = 999;
public class FinalChanger {
  public static void main(String[] args) {
    Final.i = 123;
    System.out.println(Final.i);
}1) Compile both without the final keyword in Final.java
2) Put final into Final.java, and recompile.
3) Run javac -cp . FinalChanger
Exception in thread "main" java.lang.IllegalAccessError
        at FinalChanger.main(FinalChanger.java:3)
:; javap -s -c -verbose -classpath . Final
Compiled from "Final.java"
public class Final extends java.lang.Object
  SourceFile: "Final.java"
  minor version: 0
  major version: 50
  Constant pool:
const #1 = Method       #3.#14; //  java/lang/Object."<init>":()V
const #2 = class        #15;    //  Final
const #3 = class        #16;    //  java/lang/Object
const #4 = Asciz        i;
const #5 = Asciz        I;
const #6 = Asciz        ConstantValue;
const #7 = int  999;
const #8 = Asciz        <init>;
const #9 = Asciz        ()V;
const #10 = Asciz       Code;
const #11 = Asciz       LineNumberTable;
const #12 = Asciz       SourceFile;
const #13 = Asciz       Final.java;
const #14 = NameAndType #8:#9;//  "<init>":()V
const #15 = Asciz       Final;
const #16 = Asciz       java/lang/Object;
public static final int i;
  Signature: I
  Constant value: int 999
public Final();
  Signature: ()V
  Code:
   Stack=1, Locals=1, Args_size=1
   0:   aload_0
   1:   invokespecial   #1; //Method java/lang/Object."<init>":()V
   4:   return
  LineNumberTable:
   line 1: 0
:; javac -version
javac 1.6.0_06
:; java -version
java version "1.6.0_06"
Java(TM) SE Runtime Environment (build 1.6.0_06-b02)
Java HotSpot(TM) Client VM (build 10.0-b22, mixed mode)