January 18, 2001 | My article last week on Java touched a nerve with readers. After reading the column, more than 100 people clicked the "mailto" link on my byline and let me know precisely how they felt -- and hundreds more wrote angry letters to the editor. I tried to respond to the first 50 or so e-mails. But when the mail kept pouring in after a week, I asked my editor if I could write a response for all to read.

Reactions to the article were mixed, with roughly 40 percent agreeing with my conclusion and 55 percent calling me names, cursing at me with their keyboards and saying that I don't know beans about programming. The remaining 5 percent were the most curious of all -- they said that I pulled my punches, that I wasn't harsh enough on the Java blight.

It's easy to understand how the article could engender such varied responses. Java is a huge industry. There are tens of thousands of companies using Java and hundreds providing tools for the language. And since there is so much disparity between the programmers that are bad at Java and those who are good at it, an attack on Java as a whole can be very threatening to those at the top of the profession. Or as one programmer with a Hotmail account told me, "Here's this for a kicker: I make more than YOU and I'm cutting code in Java! :) Suck on my $200,000/yr as a Java Developer, dumb ass."

Considering the more literate responses, the biggest criticism was that my analysis of Java was dated. "Your article is clear, concise, accurate and two years out of date," wrote Richard Katz from Mpath Interactive. Like several other readers, Katz told me that the mainstream Java world has given up on Java-based applications -- the real action is with Java application servers.

"You also ignore that the biggest growth market for Java isn't embedded devices and the J2ME," wrote Stu Charlton, a senior consultant at Infusion Development Corp. "It's the enterprise, and the J2EE. (Enterprise consulting is, in fact, my profession.) The number of financial systems that push billions of dollars in transactions through Java is astounding, based on my experience of working at investment banks in Canada, the U.S. and Japan over the last three years."

Others wrote that Java had made their lives easier by allowing them to develop Java plug-ins for Web servers on low-cost Windows NT systems, and then move the same code to $250,000 Sun Solaris servers.

In my defense, I chose to focus on desktop applications and applets because that is where most readers will encounter Java. Sun promised that Java would be the language of choice for developing desktop applications, and Sun has never repudiated this claim. It's also instructive to look at the desktop Java experience because that is where we have the most data, and that is where it is easiest to draw conclusions.

The fact is, it's somewhat easier to understand Java's contribution -- and its costs -- when you consider server-based systems. On these systems, Java's automatic memory management makes it a lot easier to write a reliable application server. And the plug-in nature of the Java class files makes it easier to write with systems like BEA WebLogic. But this ease comes at a price. I've heard of many Java installations where the server steadily uses up more memory as the day goes on, and as a result the servers need to be rebooted every night. There are other ways that performance can suffer. Some readers wrote to me that they have Java running just as fast as C; others wrote that they saw 10-fold increases in server performance when they swapped out an application written in Java for one written in C.