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Softpanorama Java Bulletin, 2000

Creating a Classpath By S. Lee Henry

After struggling for hours with some problems that ultimately boiled down to an insufficient Java classpath, I learned how to create a path statement on the fly. For anyone not familiar with Java and not wishing to be, the technique that I used might prove useful since it can be applied to other Unix paths as well.

One of the reasons that I needed to develop a clever approach to creating my java.classpath relates to a limitation on Unix systems. The vi editor doesn't seem to appreciate lines exceeding 2,000 characters (or thereabouts). I was having problems with the single line in my jsm.properties file that defines the java.classpath -? the classpath that JRun uses to process Java code. Since I could not directly edit the line, the best approach seemed to be to disassemble and rebuild it. The tool that I chose for the task was the Unix tr (translate) command.

Like most, if not all, paths in Unix, colons separate java.classpath elements. A java.classpath might look like this:

    java.classpath=/usr/java1.3/lib/jsp.jar:/usr/java1.3/lib/wcca.jar

In my case, the classpath included many more elements. It had, in fact, more than 100 elements for one particular system. To make the line that defined the path accessible for editing, I ran the file through a tr filter like so:

    boson% cat jsm.properties | tr ":" "\012" > hold.$$

This command created a file in which every element in my classpath was on a line by itself. This enabled me to change or remove lines as needed, and to add elements that were missing. If my java.classpath looked like the example shown above, after this manipulation, it would have looked like this:

    java.classpath=/usr/java1.3/lib/jsp.jar
    /usr/java1.3/lib/wcca.jar

When I finished my editing, I added a colon back to each line using this vi command (from the line where the "java.classpath" line began:

    :s/$/:/105

This added a colon to the end of the current line and the following 104 lines. Since I wasn't sure if the classpath would be valid if it ended in a colon, I avoided adding a colon there. It would have been nearly as easy to remove an extra colon and I wouldn't have needed a line count.

On another system, I went even further. I created a java.classpath completely from scratch by first collecting a list of all of the jar files on the system using a find command such as this:

    boson% find / -name "*.jar" -print > jarfiles

I also looked for files ending in .zip since these might also be Java files.

    boson% find / -name "*.zip" -print >> jarfiles

I then reviewed the contents of my jarfiles file to make sure any zip files that I included related to my Java application. After checking the entries my jarfiles file, I added "java.classpath=" to the top and then proceeded to turn this file into a single line, again using the Unix tr command.

    boson% cat jarfiles | tr -d "\012" >> jsm.properties

This removed all the linefeeds from the file, but left the appended line without a linefeed. The final step was:

    boson% echo "" >> jsm.properties

I then had a single line defining my java.classpath at the end of my jsm.properties file. I restarted JRun and everything ran fine after that. I like happy endings. Don't you?

[Jul 2, 2000] JavaBoutique: Open Source Shopping Cart [Part 2]

"The two methods for creating persistence (reloading and pseudo-constructors) cooperate beautifully. Our shopping cart, for instance, is created once, and then never destroyed. Applet reload gives it continuing access to the underlying HTML, through Javascript and LiveConnect, and through the applet lifecycle, which can pass current context information to the persistent class."  

[Jul 2, 2000] JavaBoutique: Open Source Shopping Cart [Part 1]

"The Open Source shopping cart solves these problems. It comes in two versions-- one for the small web designer, the other for the large company. We will first examine the small business version."


Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

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Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D


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Last modified: March 12, 2019