Avoid printStackTrace(); use a logger call instead

Solution 1:

It means you should use logging framework like logback or log4j and instead of printing exceptions directly:

e.printStackTrace();

you should log them using this frameworks' API:

log.error("Ops!", e);

Logging frameworks give you a lot of flexibility, e.g. you can choose whether you want to log to console or file - or maybe skip some messages if you find them no longer relevant in some environment.

Solution 2:

If you call printStackTrace() on an exception the trace is written to System.err and it's hard to route it elsewhere (or filter it). Instead of doing this you are advised using a logging framework (or a wrapper around multiple logging frameworks, like Apache Commons Logging) and log the exception using that framework (e.g. logger.error("some exception message", e)).

Doing that allows you to:

• write the log statement to different locations at once, e.g. the console and a file
• filter the log statements by severity (error, warning, info, debug etc.) and origin (normally package or class based)
• have some influence on the log format without having to change the code
• etc.

Solution 3:

A production quality program should use one of the many logging alternatives (e.g. log4j, logback, java.util.logging) to report errors and other diagnostics. This has a number of advantages:

• Log messages go to a configurable location.
• The end user doesn't see the messages unless you configure the logging so that he/she does.
• You can use different loggers and logging levels, etc to control how much little or much logging is recorded.
• You can use different appender formats to control what the logging looks like.
• You can easily plug the logging output into a larger monitoring / logging framework.
• All of the above can be done without changing your code; i.e. by editing the deployed application's logging config file.

By contrast, if you just use printStackTrace, the deployer / end user has little if any control, and logging messages are liable to either be lost or shown to the end user in inappropriate circumstances. (And nothing terrifies a timid user more than a random stack trace.)

Solution 4:

In Simple,e.printStackTrace() is not good practice,because it just prints out the stack trace to standard error. Because of this you can't really control where this output goes.