JAVA Files For BitInputStream Error

Question

Hi there,
I wrote a little test application for a bitreader, but there always is an exception, when I execute the program, does someone know why?
import java.io.*;
class Test
     public static void main(String[] args)
          try{
          File file = new File("test.dat");
          FileOutputStream fileOUT = new FileOutputStream(file);
          BitOutputStream fileBin = new BitOutputStream(fileOUT);
          fileBin.writeBit(1);
          fileBin.writeBit(0);
          fileBin.closeStream();
          fileOUT.close();
          catch(Exception e){
               System.out.println("Fatal error using OUT");
          try{
          System.out.println("1");
          BitInputStream bitIN = new BitInputStream("test.dat");
          System.out.println("1");
          if(bitIN.readBit()){
                         System.out.println("1");
               System.out.println(1);
          else{
                         System.out.println("1");
               System.out.println(0);
          if(bitIN.readBit()){
               System.out.println(1);
          else{
               System.out.println(0);
          bitIN.close();
          catch(Exception e){
               System.out.println("Fatal error using IN");
import java.io.*;
import java.lang.Exception;
public class BitOutputStream extends ByteArrayOutputStream {
private FileOutputStream myFileOS;
private int bitsWritten;
private int bitPosition;
private byte[] myByte;
private final static int NUM_BITS_IN_BYTE = 8;
private final static int END_POSITION = -1;
* Default constructor.
public BitOutputStream() {
this(null);
* Constuct based upon a FileOutputSteam to write to
public BitOutputStream( FileOutputStream fos ) {
super();
myFileOS = fos;
bitsWritten = 0;
myByte = new byte[1];
resetByte();
* Reset the byte and position marker.
private void resetByte() {
bitPosition = NUM_BITS_IN_BYTE-1;
myByte[0] = (byte)0x00;
* Write to my super's buffer.
private void flushByte() {
write( myByte, 0, 1 );
bitsWritten = bitsWritten + 8;
resetByte();
* Write a bit to the stream.
* If bit == "0", writes a '0' bit.
* If bit == "1", writes a '1' bit.
public void writeBit( int bit ) {
if( bit != 0 && bit != 1 ) {
System.err.println( "<BitOutputStream>: only 1's and 0's can be written" );
if( bitPosition == END_POSITION ) {
flushByte();
if( bit == 0 ) {
bitPosition--;
else if( bit == 1 ) {
myByte[0] = (byte)(myByte[0] | (0x01 << bitPosition));
bitPosition--;
* Writes to the file if a FileOutputStream is set.
public void flushToFile() {
if( myFileOS == null ) {
System.err.println( "No FileOutputStream set" );
else {
try {
// Flush any excess to my super's buffer
if( bitPosition >= END_POSITION && bitPosition != NUM_BITS_IN_BYTE-1 ) {
flushByte();
// Have my super write to the File
writeTo( (OutputStream)myFileOS );
catch( Exception e ) {
System.err.println("<BitOutputStream>: error flushing to file");
e.printStackTrace();
* Close the stream.
public void closeStream() throws Exception {
try {
super.close();
catch( Exception e ) {
System.err.println("<BitOutputStream>: error while closing");
e.printStackTrace();
throw( new Exception( "<BitOutputStream>: error closing stream" ));
import java.io.*;
public class BitInputStream {
private static final int BYTESIZE = 8;
private int myUnusedBits;
private byte myCurrentByte;
private int myTotalBytesRead;
private DataInputStream myData;
// Create an input bit stream for the file
public BitInputStream (String file) throws FileNotFoundException {
     myData = new DataInputStream(new FileInputStream(file));
     myUnusedBits = 0;
     myCurrentByte = 0;
     myTotalBytesRead = 0;
public int getBytesRead( ) { return myTotalBytesRead;}
public String toString( ) { return "(Total = " + myTotalBytesRead + ", Unused bits = "
                         + myUnusedBits + ")"; }
// Close the underlying DataInputStream and release resources                     
public void close( ) throws IOException {
     myData.close();
     myUnusedBits = 0;
// If a partial byte has been read throw, throw it away
public void flush( ) {
     myUnusedBits = 0;
     myCurrentByte = 0;
// Read the next bit
public boolean readBit( ) throws IOException {
     // If all the bits in the current byte have been used, read another
     if (myUnusedBits <= 0) {
     myCurrentByte = myData.readByte();
     myTotalBytesRead++;
     myUnusedBits = BYTESIZE;
     boolean bitRead = (myCurrentByte < 0); // is sign bit set?
     myCurrentByte = (byte)(myCurrentByte << 1); // shift left by 1 to move next bit in
     myUnusedBits--;
     return bitRead;
public byte readByte( ) throws IOException {
     myUnusedBits = 0; // If a partial byte was read, throw it away
     byte t = myData.readByte( ); // Get the byte
     myTotalBytesRead++; // If read successful, update byte count
     return t;
public int readInt( ) throws IOException {
     myUnusedBits = 0; // If a partial byte was read, throw it away
     int t = myData.readInt( ); // Get the int
     myTotalBytesRead+=4; // If read successful, update byte count
     return t;
thx
Charly

Answer 1

Probably because there's an error in your program. It would be easier to say something useful if we knew what the error was and what line of code caused it.