Java utilities - JavaTech: An Introduction to Scientific and Technical Computing with Java - page 353

the java.util.regex.Pattern class for complete documentation [5,6]. In
its simplest form, searching for a regular expression consisting of a single char-
acter finds a match of that character. For example, the character 'x' is a match for
the regular expression “x”.
The split() method takes a parameter giving the regular expression to use
as a delimiter and returns a String array containing the tokens so delimited.
Using split() , the first example above becomes
String str ="This is a string object";
String[] words = str.split ("");
for (int i=0; i < words.length; i++)
System.out.println (words[i]);
To use “* „ as a delimiter, simply specify “* „ as the regular expression:
String str ="A*bunch*of*stars";
String[] starwords = str.split ("*");
For most string-splitting tasks, the String.split() method is much eas-
ier and more natural to use than the StringTokenizer class. However,
StringTokenizer is still useful for some tasks. For example, an overloaded
StringTokenizer constructor allows you to specify that the tokens to be
returned include the delimiter characters themselves.
10.12 Calendar , Date , and Time
Java offers several classes for dealing with dates and times. Some are in the
java.util package:
GregorianCalendar (a subclass of the abstract Calendar class)
Date
These two are in java.text :
DateFormat and its subclass SimpleDateFormat
The GregorianCalendar class can be used to represent a specific date accord-
ing to the Gregorian calendar (and the Julian calendar before that). Methods are
provided to compare calendar objects such as whether one date came before or
after another. The Calendar base class, which is abstract, holds static methods
that give information such as the current date and time:
Calendar this - moment = Calendar.getInstance ();
The hierarchy implies that there could be other calendar subclasses, e.g. Chinese,
but none has appeared in the core language as of version 5.0.