Log4J & Log4Cocoa

Jonathan Rentzsch & Bob Frank

Tuesday, July 8th 2003, 7:00-9:00pm
Building OCC, Room 128 C & D


Ideally, explicitly adding logging statements to your code would be unnecessary. All software would be source-level debuggable at all times. Sadly, this is not the case. Compilers, deployment environments, threads and distributed objects all conspire against us.

So if you can't easy throw a debugger at a running or deployed program, how do you tell what it's doing (and what's going wrong!)? Well, logging is the age-old technique of weaving code into your program that outputs a trace of what the program is doing.

Most languages offer an ability to output a string, which can be used for logging purposes. Here I'm thinking of calls like C's printf, perl's print and Java's System.out.println(). But there's a better way to add logging to software: a dedicated logging package like Log4J.

Log4J is a logging package written in Java distributed under a BSD-style license by the Apache group, and has been ported to a number of languages. It has a number of advantages over the simplistic System.out.println(), including:

In addition, Bob Frank -- leader of the Cocoa And WebObjects User Group in Chicago -- will speak about his Log4Cocoa package, which is a port of Log4J to Objective-C and Mac OS X's Cocoa API. Bob will offer his insights on how the C preprocessor and Objective-C's object runtime services enhance the baseline package.

Speaker Bio

Jonathan 'Wolf' Rentzsch ( is the embodiment of Red Shed Software and runs a Macintosh Programming Special Interest Group in Schaumburg. In between reading and coding, he'll venture outside for a bike ride or will pontificate on various list servers about obscure topics. He encourages his competitors to purchase and mandate the use of products with the most market share.

Bob Frank is a Senior Engineer in Apple's Educational consulting group. He works with all Apple technologies, but is primarily focused on designing and developing Java based applications using Apple's application server WebObjects and using Apple's object persistence technology Enterprise Objects. In addition, he also helps run the Chicago Cocoa and WebObjects User Group (CAWUG), a local programing user group.

Getting to the meeting

The next general meeting of UniForum Chicago will be from 7:00 pm to 9:00 pm on Tuesday, July 8th, 2003, at the College of DuPage, building OCC - room 128 C & D.

        College of DuPage
        Building OCC, Rm. 128 C & D
        Fawell Boulevard and Lambert Rd.
        Glen Ellyn, IL 60137-6599

Take 355 to Butterfield Rd (Rt 56). Take Butterfield West to Lambert Rd, then Lambert Rd North to 22nd St. Turn left and look for Lots 9 or 10 (A or B) on the left side of Fawell Blvd.
Walk south to Building OCC, room 128cd is near the mid north-west corner of the building.

All UniForum Chicago SIG meetings are open to the public free of charge.

Contact Michael Potter at (630) 829-7033 or for additional information about the meeting.

For more information about UniForum Chicago contact

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