log4j vs system.out.Println()

[Amirtharaj Chinnaraj]

hi guys

what is the difference between printing

a content in console using log4j and

system.out.println().peoples use to say

that using system.out.println() is performance

loss

i think log4j is written in java so it may also

use system.out.println() to print the content in console


then why peoples preferring log4j ?

i think i have posted this topic in correct forum
i am not including any web related techonology


regards
amir

[Peter Chase]

If all you're ever going to want to do is print a few messages to console, then System.out.println() is fine.

A proper logging system, like Log4J, adds all sorts of features that are very useful in real applications. You can direct the output to different places (console, file, network etc.). You can tell it to output only a subset of the messages, without having to recompile. You can get timestamp on each message etc.

If you're writing a small utility program for your own use, which will never expand into something more, use System.out.println(). If you're writing industrial-strength code, or a utility library for others, using a proper logging system is the professional thing to do.

Log4J is not the only one, by the way.

[Amirtharaj Chinnaraj]

thanks perter

for your reply

iam scrutinize only in the performance

some bloggers have told that system.out.prrintln() will consume

to much of performance than log4j

i think log4j will consume more performance because it

have has to print more information

regards
amir

[Christophe Verré]

log4j's ConsoleAppender uses either System.out or System.err, so what you were told is not correct. And as log4j is wrapping the standard streams, it is a bit slower than using System directly.

[Christophe Verré]

Amirtharaj, could you please avoid to separate each lines with a blank line. It makes it really difficult to read. Thank you

[Rahul Bhattacharjee]

Configuration is another factor for using log4j over SOP's.
Even while you are developing you application you can set the log4j level to DEBUG and at production you can turn that to ERROR or FATAL.

Logging too much statements might be a performance overhead .You should always follow the best practices for better performance.
Check out the last section of document.
http://logging.apache.org/log4j/docs/manual.html

[steve souza]

Even if you use System.out.println() I would use a wrapper logging class that will later allow you to use log4j while only changing this class and not all of your apps logging methods. I don't have a good example of all the methods you should include, but something like this (as well as the methods that take an exception would be good i.e. error(message, exception))

   
  public class Logger {
 
    // Creation & retrieval methods:
    public static Logger getRootLogger();
    public static Logger getLogger(String name);
 
    // printing methods:
    public void trace(Object message);
    public void debug(Object message);
    public void info(Object message);
    public void warn(Object message);
    public void error(Object message);
    public void fatal(Object message);
 
 
} 

Initiallly debug might look like this:

 
public void debug(Object message) {
  System.out.println(message);
}
 
// later you could change it to use log4j
public void debug(Object message) {
  logger.error(message);
}

[Amirtharaj Chinnaraj]

thanks one and all i want to know what are all the similar opensource tools like log4j that can be used in java platform

[Christophe Verré]

Do you mean open source for logging ?

[Jesper de Jong]

Since Java 1.4, the standard API itself contains a logging facility: see the API documentation of package java.util.logging.

However, a lot of people still seem to prefer Log4J above the standard logging API. Log4J is probably a bit more flexible than the standard logging API.

[v ray]

Yeah, for normal small programs where performance or any other similar issue is never a problem, SOP's are fine, but when running a real time project, its best to use some kind of logger. log4j is great, but even the logger from the util package is better than SOPs...Another thing which intruiges me is assertions, need to use it more!