Why do we need FileInputStream in = null; line before try block?

This code from oracle i/o tutorial:

public class CopyBytes {
public static void main(String[] args) throws IOException {

    FileInputStream in = null;
    FileOutputStream out = null;

    try {
        in = new FileInputStream("xanadu.txt");
        out = new FileOutputStream("outagain.txt");
        int c;

Why these lines

FileInputStream in = null;
FileOutputStream out = null;

not included to try block in this way (without = null)?

 FileInputStream in = new FileInputStream("xanadu.txt");
 FileOutputStream out = new FileOutputStream("outagain.txt");

You need to declare in and out outside try {...} because you need to close these resources in the finally {...} block.

FileInputStream in = null;
FileOutputStream out = null;

try {
  in = new FileInputStream("xanadu.txt");
  out = new FileOutputStream("outagain.txt");
  int c;
  ....
} catch(Exception e) {

} finally {
   try {
     if(in != null) {       
       in.close();
     }
     if(out != null) {
       out.close();
     }
   catch(Exception e) {...}
}

If you declare them inside the scope of try {...} the compiler will complain that they could not be resolved.

If you do:

try {
  FileInputStream in = new FileInputStream("xanadu.txt");
  FileOutputStream out = new FileOutputStream("outagain.txt");
  int c;
  ....
} catch(Exception e) {

} finally {
   try {
     if(in != null) { //in could not be resolved error by compiler       
       in.close();
     }
     if(out != null) { //out could not be resolved...
       out.close();
     }
   catch(Exception e) {...}
}