FileInputStream.available() & Thread.dumpStack()

Question

Hello !
Although the copying of text is OK and text is copied correctly from Source.txt to Target but
there are a few things I need hlep with :
1. Is dumpStack() the correct method to get a complete Stack trace in case of an exception.
2. fa.available() is giving zero '0' in class CopyingTxt but is working correctly in the main() giving an actual number of bytes of files size.
God bless you all.
NADEEM.
import java.io.* ;
public class CopyingText {
public static void main(String args[])  { 
Thread t = new Thread();
  try {
   System.out.println("Enter java CopyingText Source.txt Target.txt");
   FileInputStream  a = new FileInputStream(args[0]);
   FileOutputStream b = new FileOutputStream(args[1],true);        
   System.out.println("Source size: " + a.available());
   System.out.println(a.getFD());
    CopyingTxt rw  = new CopyingTxt(a,b);
    rw.fileCopying();
//    rw.bytesAvailable();             Giving IOException: Bad file descriptor : Reason ?
  } catch(Exception e) {
    System.out.println("Exception : main() :" + e );
    t.dumpStack();
class CopyingTxt   {
  private int i  , j  ;
  FileInputStream  fa ;
  FileOutputStream fb ;
  CopyingTxt(FileInputStream a, FileOutputStream b) {
   fa = a ;
   fb = b ;
  public int bytesAvailable() throws IOException {
   System.out.println(fa.getFD());
   System.out.println(fa.available());
   return fa.available() ;
  public void fileCopying() throws IOException {
   do {
    i = fa.read();
    j++ ;                                  
    if(i != -1) fb.write(i) ;
   } while(i != -1);                       //EOF condition  -1 .
   System.out.println("Bytes read : " + (j-1) + " / " + fa.available());
   bytesAvailable();
   fa.close();
//    fa.finalize();
   fb.close();
//    fb.finalize();
}

Answer 1

On the other hand
Thread.dumpStack()
Prints a stack trace of the current thread. This method is used only for debugging.
is meant to get a Thread stacktrace, in case of Exceptions we usually print out:
Throwable.printStackTrace()
Prints this throwable and its backtrace to the standard error stream.
Are you sure you want the Thread stacktrace???
FreeZotic
Just starting with the Thread chapter!
forgive forgive