Errata

(Error in -> Chapter 1: Yet another language?)

The paragraph finishes a discussion about application and user-level
security in Java by giving a general explanation about the use of digital
signatures and certificates. It states that the details of this topics will
be covered in Chapter 3 (Tools of the trade). This is incorrect because it
is until Chapter 20 (Applets) that the digital signatures and certificates
are adressed in full.

When running HelloJava4 under OS X, the paintComponent method has an odd side effect.
Since the default window on OS X is actually stripped, drawing theMessage with the
color set to the background color actually leaves a white outline of the text against
the stripes.

I was able to resolve this by changing the code from

public void paintComponent(Graphics g) {
g.setColor(blinkState ? getBackground() : currentColor());
g.drawString(theMessage, messageX, messageY);
}

to

public void paintComponent(Graphics g) {
if(blinkState)
g.drawString(theMessage, messageX, messageY);
}

"Java source code can be written using the Unicode character set encoding
and stored either in its full 16-bit form or with ASCII-encoded Unicode
character values"

"...the first 256 characters are defined to be identical to the first 256
characters in the ISO8859-1 (Latin-1) encoding..."

I think this may be true of UTF-8, but not of Unicode. JDK 1.3 javac is
horribly confused by source code stored in Unicode format.

(Chapter 4)I would like to see more code examples in chapters 4-7.
These are important concepts for learning Java and I need programming
examples to run and play with to help me understand the concept.

and not upper case.

This detail is important because changing the case for datatype means
different things in java.

javac under JDK 1.3 or 1.2.2 does not complain about unreachable statements
(not by default, anyway). In fact, I'm sure I saw this mentioned somewhere
as a recommended technique for conditional compilation, in lieu of #ifdefs.

Both code examples use "Class" rather than "class".

Text refers to:

"...just like the C routine string():"

The correct name of the routine is "strcmp" so the sentence should read:

"...just like the C routine strcmp():"

Incorrect return type for remove, get, set methods:

Book has:
public void remove(int index)
...
public void get(int index)
...
public void set(int index, Object element)
...

Should be (per Java 2 Platform SE v1.3 API documentation)
public Object remove(int index)
...
public Object get(int index)
...
public Object set(int index, Object element)
...

e.hasMoreElements

should be:

e.hasMoreElements()

In the line :
String name = e.nextElement();

Function e.nextElement() returns an Object object. Type of the returned value should
be changed to String.
String name = (String) e.nextElement();

The sentence "The java.lang.System class provides access to basic system
environment information through the static System.getProperty() method."
should say that System.getProperties() is the method to do this. The
following sentence states that getProperty() returns a Properties table,
but it is getProperties() that does this.

Paragraph states that the ISO standard for country codes is ISO639, and for
languages is ISO3166. This is backwards: ISO639 is the set of codes for
languages, and ISO3166 is the set of codes for countries.

The formatting example for percentages will only print 44% if the value of progress is 0.44. Change the declaration of progress to:
double progress = 0.44;

I don't know if the page is right, because I have a pdf version of the book

13.2 Containers.
You wrote : Three of the most useful container types... . JFrame is derived from
JWindow, which is pretty...

13.2.7 Windows and Frames
You wrote : Windows and Frames are the top-level... . JFrame, on the other hand, is a
subclass of JWindow that has a border...

JFrame IS NOT a subclass of JWindow.

Object -> Component -> Container -> Window -> Frame -> JFrame
Object -> Component -> Container -> Window -> JWindow

// read results...
if ( urlcon.getResponseCode() != HttpURLConnection.HTTP_OK )
System.out.println("Posted ok!");
else {
System.out.println("Bad post...");
return;
}

... it should either have the != changed to == or the cases reversed since
this if provides the reverse functionality of what you were going for.

drawImage should be g.drawImage