Seven Common Mistakes You Should Avoid When Handling Java Exceptions
By Thorben Janssen
Handling an exception is one of the most common but not necessarily one of
the easiest tasks. It is still one of the frequently discussed topics in
experienced teams, and there are several best practices and common mistakes
you should be aware of.
Here are a few things you should avoid when handling exceptions in your
application.
Mistake 1: Specify a java.lang.Exception or java.lang.Throwable
As I explained in one of my previous posts, you either need to specify or
handle a checked exception. But checked exceptions are not the only ones you
can specify. You can use any subclass of java.lang.Throwable in a throws
clause. So, instead of specifying the two different exceptions that are
thrown by the following code snippet, you could just use the
java.lang.Exception in the throws cla... (more)
(LinuxWorld) — One of my non-profit Web sites, VarLinux.org, ran on my
modified version of the PHP-Nuke weblog package from the site's inception in
March 2001 until late November 2002. I chose PHP-Nuke as a starting point
because I was very impressed with it. However, the more I learned how to use
PHP, the more I realized that PHP-Nuke was not only a tangled mess but that I
had made it even worse with my modifications. A year later, I was faced with
the fact that VarLinux.org was not only lame because it was based on
PHP-Nuke, it was also showing its age. It lacked features of other weblogs,
and still lacked many of the features I had intended to add to the site.
If I were going to fix the code, the first thing I would do would be to make
it an object-oriented system. I toyed with the idea of converting my code
into OOP-based code, but I concluded that if the P... (more)
Related Links:
Wanted: 19 More of the Top Software People in the World Sung and Unsung
i-Technology Heroes Who's Missing from SYS-CON's i-Technology Top Twenty?"
Our search for the Twenty Top Software People in the World is nearing
completion. In the SYS-CON tradition of empowering readers, we are leaving
the final "cut" to you, so here are the top 40 nominations in alphabetical
order.
Our aim this time round is to whittle this 40 down to our final twenty, not
(yet) to arrange those twenty in any order of preference. All you need to do
to vote is to go to the Further Details page of any nominee you'd like to see
end up in the top half of the poll when we close voting on Christmas Eve,
December 24, and cast your vote or votes. To access the Further Details of
each nominee just click on their name. Happy voting!
In alphabetical order the nominees are:
Tim Berner... (more)
Preparing for an interview? Want to just revisit Java SE 7 features? Trying
to recollect or revise a Java SE programming construct? Let me take you back
in time to what was introduced first in Java SE 7? Join me for this tutorial
series on Java as we all eagerly await the official release of Java SE 9.
Java SE 7 Release Date: 28-07-2011
Java SE 7 Code Name: Dolphin
Java SE 7 Highlights
Strings in switch statements. Automatic resource management in try
statements. Improved type inference for generic instance creation, AKA the
diamond operator <>. Simplified varargs method declaration. Binary integer
literals. Allowing underscores in numeric literals. Catching multiple
exception types and rethrowing exceptions with improved type checking.
I have provided some of the most important core language enhancements for JDK
7.0, along with code samples. The examples provided bel... (more)
Gene Amdahl: Implementer in the 60s of a milestone in computer technology:
the concept of compatibility between systems
Marc Andreessen: Pioneer of Mosaic, the first browser to navigate the WWW;
co-founder of Netscape
John Vincent Atanasoff: Inventor of an electronic computer in the late 1930s
not for fun or glory, but because he had problems for it to solve
Charles Babbage: Lucasian Professor of Mathematics at Cambridge in 1828;
inventor of the 'calculating machine'
John Backus: Inventor (with IBM) of FORTRAN (FORmula TRANslator) in 1956
Ralph Baer: "The man who invented video games" (Pong)
Kent Beck: Creator of JUnit and pioneer of eXtreme Programming (XP)
Bob Bemer: One of the developers of COBOL and the ASCII naming standard for
IBM (1960s)
Tim Berners-Lee: "Father of the World Wide Web" and expectant father of the
Semantic Web
D J Bernstein: Author of qmail
Jos... (more)
Java Heap Space vs. Stack Memory: How Java Applications Allocate Memory
By Angela Stringfellow
Java applications need a certain amount of RAM on a computer to run. Each
time an object or variable is declared, it needs more RAM. Simply designating
enough memory to hold every value declared and run each method would lead to
a bloated application.
To keep application memory requirements lean, it is partitioned in ways that
require less memory and allows the application to run more quickly.
The Java Virtual Machine (JVM) divides memory between Java Heap Space and
Java Stack Memory in a way that only uses memory that's needed.
What Is Java Heap Space
It is created by the Java Virtual Machine when it starts. The memory is used
as long as the application is running. Java runtime uses it to allocate
memory to objects and Java Runtime Environment (JRE) classes.
When an object i... (more)
I wonder how many people, as I did, found themselves thrown into confusion by
the death last week of Jean Ichbiah (pictured), inventor of Ada.
Learning that the inventor of a computer programming language is already old
enough to have lived 66 years (Ichbiah was 66 when he succumbed to brain
cancer) is a little like learning that your 11-year-old daughter has grown up
and left home or that the first car you ever bought no longer is legal
because it runs on gasoline in an age where all automobiles must run on
water. How can something as novel, as new, as a computing language possibly
already be so old-fangled that an early practitioner like Ichbiah can
already no longer be with us?
The thought was so disquieting that it took me immediately back to the last
time I wrote about Ichbiah, and indeed about Ada Lovelace for whom his
language was named. It was in the context ... (more)
This article was originally published in print on December 3, 2003"Eclipse
represents the worst of Java"
Lately, there's been a lot of guff spouted about how Sun isn't joining
Eclipse. While I understand the bitterness aimed at Sun somewhat, I think
that this particular brand of talk is counterproductive and, dare I say it,
wrong. The talk tends to center around the concept of NetBeans and Eclipse
using common technology, and I think this is misguided, and here's why.
I really dislike Netbeans. I think it blows goats from here to Sussex, and
considering that I live in the middle of the US, that's a lot of goats. Given
the choice between NetBeans and... Notepad, I usually spend a minute
pondering whether I can keep remembering to check extensions on filenames
before realizing that I can, and I end up with sucky ol' Notepad instead of
bothering with NetBeans.
That sai... (more)
JDJ's Enterprise Editor, Yakov Fain (pictured) writes: If you are planning to
hit the job market, you may need to refresh some of the Java basic terms
and techniques to prepare yourself for a technical interview. Let me offer
you some of the core Java questions that you might expect during the
interviews.
For most questions I’ve provided only short answers to encourage
further research. I have included only questions for mid (*) and senior
level (**) Java developers. These sample questions could also become handy
for people who need to interview Java developers (see also the article
"Interviewing Enterprise Java Developers").
Disclaimer. This article has been originally published three or four years
ago, hundreds of thousands Java developers have read it, but I still use some
of these questions while interviewing Java developers. Guess what? Every
other Jav... (more)
This article will introduce you to Workplace Designer 2.5. We begin with a
brief overview of Workplace Designer and how you can use it to create
Workplace applications. We then take a closer look at some of the many
features included in Workplace Designer. We assume that you have experience
with Web application development. Some familiarity with IBM Workplace
products (such as IBM Workplace Collaboration Services 2.5 and IBM Workplace
Services Express 2.5) would also be helpful.
What is Workplace Designer?
If your background is in Notes/Domino programming, you can think of Workplace
Designer as a tool for providing Domino Designer-type application development
functionality to the IBM Workplace family of products. In fact, those
familiar with Domino Designer will notice a lot of similarities with many IBM
Workplace Designer features and concepts described later in thi... (more)
[This prescient article first appeared on SYS-CON.com nearly 12 months ago.]
We are entering an era of Rich Internet Applications (RIA), and many
enterprise development managers are facing the dilemma - which way to go -
remain with tried and true Java or .Net technologies or less known yet
AJAX, Flex, OpenLaszlo or a number of other vendors. This article is an
attempt to give a brief overview of what's out there on the RIA market.
Historically there have been major shifts in the software industry. We moved
from mainframes with dumb terminals to client/server. Users gained in
convenience and productivity, and mainframe systems were patronizingly
labeled as legacy. With the availability of the World Wide Web industry
visionaries turned the tables: vendors and corporate IT had been eager to get
rid of the complexity of client/server version management and technologist... (more)
Subscribe to Java EE Journal Email News Alerts
Subscribe via RSS
