PrintWriter not working !!

Question

import java.io.*;
public class FileDemo {
     public static void main(String args[]) {
          if (args.length != 1) {
               System.out.println("Must enter text to write to file");
               return;
          try {
          PrintWriter myWriter = new PrintWriter(new BufferedWriter(new FileWriter("myfile.xyz")),true);
          catch (Exception e) {
          // handle exception here
          String myString = args[0];
          myWriter.println(myString);
          myWriter.close();
}I can't understand why this won't compile :
FileDemo.java:30: cannot find symbol
symbol : variable myWriter
location: class FileDemo
myWriter.println(myString);
^
FileDemo.java:32: cannot find symbol
symbol : variable myWriter
location: class FileDemo
myWriter.close();
^
2 errors
cheers

Answer 1

Yes - any variable declared inside a block is only good for that
block.
It's sort of logical: after all, variables declared in a method
don't "leak" out of the method's block and become visible
to other methods.
In the same way you are free to create "throwaway" variables like counters in a for loop. They won't be visible - and hence won't cause
problems - outside of the block containing the loop.
In the case of try/catch blocks it may be a bit more subtle. Suppose
you were allowed to declare a variable inside a try/catch block
and use it later outside. Now an error could occur and be caught
before the variable had been initialised (or even declared). If the
"catch" bit doesn't actually exit the method you would be left with
references to something that hasn't been initialised. This is sure
to cause problems! - or at least it would except that Java never
allows this to happen.
The rule followed has the virtue of being simple: a variable is visible
in and only in the block where it's declared (including sub blocks).