Difference between System.in.read() and BufferedReader.read()

[Nathan Russell]

OK, first off - I hope this question is suitable for the Beginners section, and not the Intermediates ! - I certainly do not consider myself anything other than a Beginner ....... So, here goes nothing .....

Is there a difference in the return value / data type returned of System.in.read() and BufferedReader.read() ?
By this, I mean they both return an int - right ? An int being 16 bits ?

Heres the deal. I have written 2 methods within a console application. One reads from stdin into a StringBuffer object until eof; the other reads from a file into a StringBuffer object until eof.

I wont bore you with the entire code, but the 2 methods in question are:

// static method to read Stdin until eof, and return the whole lot as a StringBuffer object
public static StringBuffer readStdin() {
StringBuffer sb = new StringBuffer();
int readChar = 0;
while (readChar != -1) { // the loop ends when readChar is -1 (IE. eof)
// read 1 byte at a time
try {
readChar = System.in.read(); // read one char from stdin
} // end try
catch (IOException e){System.out.println("IOException on reading stdin");}
if (readChar != -1) {sb.append((char) readChar);} // append to the StringBuffer unless its eof
} // end while
return sb;
} // end readStdin method

// static method to read a file until eof, and return the whole lot as a StringBuffer object
public static StringBuffer readFile(String filename) {
StringBuffer sb = new StringBuffer();
try {
FileReader file = new FileReader(filename); // open the file
BufferedReader filereader = new BufferedReader(file); // setup a BufferedReader for the file
int readChar = 0;
while (readChar != -1) { // the loop ends when readChar is -1 (IE. eof)
// read 1 byte at a time
try {
readChar = filereader.read(); // read one char from the BufferedReader
} // end try
catch (IOException e){System.out.println("IOException on reading from the file");}
if (readChar != -1) {sb.append((char) readChar);}  // append to the StringBuffer unless its eof
} // end while
} // end try
catch (FileNotFoundException e) {System.out.println("FileNotFoundException on trying to open the file");}
return sb;
} // end readFile method

The objective of the application is to take a stream from stdin, or read a file from disk, and produce a dump of each byte in decimal, hex, and the ascii. (A lot like debug or many other file dumpers do in fact - thats not the point, its a learning excercise for me !)

If I run the application, and pipe into it a binary file - and consequently use the readStdin() method - it 'seems' to work perfectly.
If I run the app and read the same file from disk, using the readFile() method, for the most part the output is the same, but occasionally there are differences.

If I do the same with standard text files, both methods return the same results. Its only on binary files that there seems to be a difference.

Any ideas ??
Cheers

Nathan

[Marilyn de Queiroz]

BufferedReader returns an int (32 bits): The number of characters read, or -1 if the end of the stream has been reached.

InputStream returns an int (32 bits): The total number of bytes read into the buffer, or -1 is there is no more data because the end of the stream has been reached.

Note
1) an int is 32 bits, not 16 bits
2) BufferedReader reads chars, but InputStream reads bytes.

[Dirk Schreckmann]

Moving this to the I/O and Streams forum...