FileNotFoundException

All of those problems are IOExceptions so the outer try{} could catch them all with one catch{} block. But this one block would not be very specific about which type of error it caught. The constructors for FileInputStream and FileOutputStream throw FileNotFoundException when there is a problem. Its catch{} block should preceed the one for IOException.

Here is the program so far:

    . . . . 
try
{
  instr = 
  outstr = 
  try
  {
  }
  catch ( EOFException  eof )
  {
  }

}

catch( ______________________ )
{
}

catch( ______________________ )
{
}