Is println bad?

[xanderdunn]

The default scalastyle config that's provided with it has println flagged as a warning in both the token and regex rules:

 <check class="org.scalastyle.file.RegexChecker" level="warning" enabled="true">
  <parameters>
   <parameter name="regex"><![CDATA[println]]></parameter>
  </parameters>
 </check>

Is this just an example that isn't meant for production use, or is println considered bad?

[matthewfarwell]

It is just an example. There is nothing wrong with println.

However, for production code, there are better solutions, for example slf4j or log4j. So, a number of project that I have been involved with discourage the use of println. See, for example http://stackoverflow.com/questions/2750346/logger-vs-system-out-println

[xanderdunn]

@matthewfarwell Thanks. Good advice.

[eshu]

It is just an example. There is nothing wrong with println.

However, for production code, there are better solutions, for example slf4j or log4j. So, a number of project that I have been involved with discourage the use of println. See, for example http://stackoverflow.com/questions/2750346/logger-vs-system-out-println

There is PrintStream in the standard Java library, it has println in its methods and this check complains about it too. I updated the regular expression for my project:

 <check level="warning" class="org.scalastyle.file.RegexChecker" enabled="true">
  <parameters>
   <parameter name="regex"><![CDATA[(?<!\.)println]]></parameter>
  </parameters>
 </check>

Probably it should be in the scalastyle default configuration: the warning appears only for "bare" println call.