Errata

has been changed to:

http://www.oreilly.com/catalog/9781565928701/

The "o" was missing in oreilly.

"Notice the addition of a <code>start()</code> method"

now reads:

"Notice the addition of the <code>calculateDigest()</code>
method to start the thread."

one definate error is that the method declaration is out of order for

"public void synchronized sendDigest (byte[] digest) {"

it should read:

"public synchronized void sendDigest (byte[] digest) {"

AUTHOR: This is correct.

p. 161: If there are directories, already gzipped files, or other
incompressible files, the thread is likely not to exit when it
should. To fix this, move the call to incrementFilesCompressed() from
the fifth line on p. 162 to right after the line that removes a file
from the pool on p. 161. Then the run() method should read as follows:

public void run() {

while (filesCompressed != GZipAllFiles.getNumberOfFilesToBeCompressed()) {

File input = null;

synchronized (pool) {
while (pool.isEmpty()) {
if (filesCompressed ==
GZipAllFiles.getNumberOfFilesToBeCompressed()) {
System.out.println("Thread ending");
return;
}
try {
pool.wait();
}
catch (InterruptedException ex) {
}
}

input = (File) pool.remove(pool.size()-1);
incrementFilesCompressed();

}

// don't compress an already compressed file
if (!input.getName().endsWith(".gz")) {
try {
InputStream in = new FileInputStream(input);
in = new BufferedInputStream(in);

File output = new File(input.getParent(), input.getName() + ".gz");
if (!output.exists()) { // Don't overwrite an existing file
OutputStream out = new FileOutputStream(output);
out = new GZIPOutputStream(out);
out = new BufferedOutputStream(out);
int b;
while ((b = in.read()) != -1) out.write(b);
out.flush();
out.close();
in.close();
}
}
catch (IOException e) {
System.err.println(e);
}

} // end if

} // end while

} // end run

p. 163: The example is not always adding files at the begining of the
queue like it should. In the synchronized block change

pool.add(files[j]);

to

pool.add(0, files[j]);

All three versions of the join() method including the noargs variant can throw an InterruptedException. Thus the first method signature
on the page now reads:

public final void join() throws InterruptedException

This code may enter an infinite wait state.
When the main method finishes adding all the files to the pool it calls

for (int i = 0; i < threads.length; i++)
threads[i].interrupt();
}

If a thread picks up the last file and is still processing it when this
loop is called, all the threads will wake up, notice that the pool is
empty, but the condition (filesCompressed ==
GZipAllFiles.getNumberOfFilesToBeCompressed()) will still be false until
the running thread finishes the last file. This will place all other
threads in a wait state never to be woken up.

This happened to me which is how I was alerted to the problem.

A way to fix this is to ammend the loop to read:

while(threads[0].getFilesCompressed() != filesToBeCompressed);
for (int i = 0; i < threads.length; i++ ) {
threads[i].interrupt();
}

Of course this will necessitate adding a
public int getFilesCompressed() method to the GZipThread class.

AUTHOR: This is correct.

p. 170: In the third text paragraph, "explicitly via getAddress"
should be "explicitly via getHostName".

p. 189: In the processLogFile() method in Example 6-11, PooledWeblog,
the body of the try block should read as follows:

String entry = in.readLine();
while (entry != null) {

if (entries.size() > numberOfThreads) {
try {
Thread.sleep((long) (1000.0/numberOfThreads));
}
catch (InterruptedException e) {}
continue;
}

synchronized (entries) {
entries.add(0, entry);
entries.notifyAll();
}

entry = in.readLine();
Thread.yield();

} // end while

In the processLogFile() method in Example 6-11, PooledWeblog, bin.readLine() now reads in.readLine().

Example 9-5 is a complete applet that downloads a sound file called
gong.au, which is located in the same directory as the applet, ...

should be:

Example 9-5 is a complete applet that downloads a sound file called
beep.au, which is located in the sounds directory just below the document
base, ...

try {
InetAddress OReilly = InetAddress.getByName("www.oreilly.com");
Socket OReillySocket = new Socket(OReilly, 80);
// send and receive data...
}
catch (UnknownHostException e) {
System.err.println(e);
}
catch (IOException e) {
System.err.println(e);
}

try {
InetAddress fddi = InetAddress.getByName("fddisunsite.oit.unc.edu");
Socket OReillySocket = new Socket("www.oreilly.com", 80, fddi, 0);
// work with the sockets...
}
catch (UnknownHostException e) {
System.err.println(e);
}
catch (IOException e) {
System.err.println(e);
}

try {
InetAddress metalab = InetAddress.getByName("metalab.unc.edu");
InetAddress oreilly = InetAddress.getByName("www.oreilly.com");
Socket oreillySocket = new Socket(oreilly, 80, metalab, 0);
}
catch (UnknownHostException e) {
System.err.println(e);
}
catch (IOException e) {
System.err.println(e);
}

the finally block was attached to the wrong try block. It is now inside the for loop. Here's
the corrected program:

import java.net.*;
import java.io.*;

public class PortScanner {

public static void main(String[] args) {

String host = "localhost";

if (args.length > 0) {
host = args[0];
}

try {
InetAddress theAddress = InetAddress.getByName(host);
for (int i = 1; i < 65536; i++) {
Socket connection = null;
try {
connection = new Socket(host, i);
System.out.println("There is a server on port "
+ i + " of " + host);
}
catch (IOException e) {
// must not be a server on this port
}
finally {
try {
if (connection != null) connection.close();
}
catch (IOException e) {}
}
} // end for
} // end try
catch (UnknownHostException e) {
System.err.println(e);
}

} // end main

} // end PortScanner

InterruptedException

has been changed to:

InterruptedIOException

in the 3rd code snippet it says:
ia = new InetAddress("metalab.unc.edu");
shouldn't it say
ia = InetAddress.getByName("metalab.unc.edu");

Their is no public constructor for InetAddress(jdk 1.3)

"GET / HTTP 1.1"

Now reads:

"GET / HTTP/1.1"

"POST /cgi-bin/register.pl HTTP 1.0"

Now reads:

"POST /cgi-bin/register.pl HTTP/1.0"

"POST /cgi-bin/post-query HTTP 1.0"

Now reads:

"POST /cgi-bin/post-query HTTP/1.0"

java.io.Permission

should be:

java.security.Permission

"HEAD / catalog/jfcnut/index.html HTTP 1.1"

Now reads:

"HEAD / catalog/jfcnut/index.html HTTP/1.1"

"OPTIONS /xml/ HTTP 1.1"

Now reads:

"OPTIONS /xml/ HTTP/1.1"

"DELETE /javafaq/1999march.html HTTP 1.1"

Now reads:

"DELETE /javafaq/1999march.html HTTP/1.1"

"PUT /hello.html HTTP 1.0"

Now reads:

"PUT /hello.html HTTP/1.0"

"TRACE /xml/ HTTP 1.1"

Now reads:

"TRACE /xml/ HTTP/1.1"

"TRACE /xml/ HTTP 1.1"

Now reads:

"TRACE /xml/ HTTP/1.1"

"TRACE /xml/ HTTP 1.1"

Now reads:

"TRACE /xml/ HTTP/1.1"

"HTTP 1.1 200 OK"

Now reads:

"HTTP/1.1 200 OK"

"HTTP 1.1 404 Not Found"

Now reads:

"HTTP/1.1 404 Not Found"

"HTTP 1.1 301 Moved Permanently"

Now reads:

"HTTP/1.1 301 Moved Permanently"

"HTTP 1.x"

Now reads:

"HTTP/1.x"

"HTTP 1.x"

Now reads:

"HTTP/1.x"