Java 5 – Unleash the Tiger on Your Next Project
by Kyle Gabhart
Introduction
On May 23rd, 1995, Sun Microsystems announced the public release
of the Java technology. Since that time, we have seen the Java
platform evolve from a simple desktop and browser-based
technology into a robust, distributed enterprise technology. As
we enter the fourth quarter of 2004, the latest version of the
Java Standard Edition platform, codenamed "Project Tiger",
has been released as Java 5. If you are wondering what
happened to Java’s 3 and 4, read on. We’ll first learn a faster
way to count to five, followed by an exploration of the new
features available with Java 5, and finally an analysis of the
new release.
1, 2…5??
In the cult classic, Monty Python and The Holy Grail, there is a
scene where King Arthur decides to use the Holy Hand Grenade of
Antioch to fight a viscous rabbit. Brother Maynard reads the
instructions for the use of the grenade and goes into great
length to indicate that you should pull the pin and count to
three (“Three shall be the number of the counting, and the
number of the counting shall be three. Four shalt thou not
count, neither count thou two, excepting that thou then
proceedest on to three…”). In spite of these explicit
instructions, King Arthur pulls the grenade pin and counts: "1,
2, 5!".
Sun’s marketing team evidently took counting lessons from this
film. The first production release of Java was version 1.0.2.
The next release was Java 1.1. Then there were a series of
incremental 1.1.x releases. When Java 1.2.1 was released, the
platform was renamed Java 2 to reflect the substantial changes
in the platform between the 1.1.x releases and the 1.2.x
releases. The Java 1.3.x and Java 1.4.x releases were also a
part of the Java 2 platform. Now that Java 1.5.0 (known
officially as "J2SE 5.0") has arrived, a new name is being used
to indicate the substantial changes that have been made in the
platform. That new name is Java 5 – 1, 2, 5!
Java 5 features
The new features in Java 5 can roughly be organized into four
categories: enhanced language features, Virtual Machine
upgrades, library updates, and desktop (UI) enhancements.
Language Features
There is a long list of language features that could be
mentioned, but we will only take time to address some of the
most significant developments.
Enumerated types – An enumerated type is a datatype
containing a fixed set of constant values. As implemented in
J2SE 5.0, enums are object-oriented (users can define methods
and fields) and typesafe.
Formatted I/O – Console output has been enhanced by
implementing printf-style formatters, enabling many legacy C
applications to be ported without changing the expected output
format. On the input side of the house, the Scanner API has been
provided to offer developers a more robust mechanism for reading
in data types rather than simply parsing strings from buffered
System.in calls.
Generic types – Perhaps the most significant enhancements
made to the Java language revolve around the introduction of
generic types. Gone are the days when Java developers must toil
and sweat to cast objects up and down the type hierarchy. With
generic types, a collection’s type can be specified at compile
time to permit compile type checks and ease development by
providing implicit type casting. Additionally, primitive types
are now able to automatically convert (autoboxing/unboxing)
between the primitive type and its corresponding Object wrapper
(int <----> Integer, boolean <----> Boolean, char <----> Char,
etc.).
Metadata – J2SE 5.0 now supports the inclusion of
metadata related to Java classes, interfaces, fields, and
methods. Development tools are the intended consumers for this
metadata to support the automated insertion of additional source
code, debugging functionality, and creation/modification of
external XML files or configuration files to support application
runtime and deployment.
Varargs – With J2SE 5.0, support for passing a variable
number of arguments into a method has been added. By using a
special notation (…) in the method signature’s parameter list,
an ad hoc Object array can be created.
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