What is the difference between system.out and system.err

Collectives on Stack Overflow. Learn more. Asked 11 years, 4 months ago. Active 1 year ago. Viewed k times. Improve this question. Add a comment. Active Oldest Votes. Improve this answer. Carlos G. Also, System. You are right, but I couldn't by god remember the right names Using C has clearly been bad for my low-level programming skills — Carlos G. Paul Richter Paul Richter 5, 2 2 gold badges 17 17 silver badges 22 22 bronze badges.

I think this is the best answer, as it explains the meaning of the streams. As well as being unpredictable across platforms, consoles are also unpredictable across web browsers.

By typing a question mark, you get a list of useful debugging commands that can be executed from the console. The console is turned off by default, and users must explicitly request that it be turned on.

Furthermore, mixing and matching a command line and a graphical user interface is generally a bad idea. Some versions of Microsoft Internet Explorer do not have a visible console. Instead, data written on System. On the Mac the log file is called Java Message Log. To turn this option on, select the Options If you absolutely must use a console in your applet, the following list shows several third-party consoles that work in Internet Explorer.

Some provide additional features over the bare-bones implementation of Netscape. Of course, URLs can get stale rather quickly. Specifically, System. System class. PrintStream , a subclass of java. Normally, output sent to System. As a general rule, the console converts the numeric byte data System. The user is more inclined to output is system.

Although this may seem obvious, many developers do not understand why errors and debugging use System. If you use Err to print out a string, the console in eclipse will appear in red. When outputting a stream, the JVM and the operating system collectively decide when to output the stream. That is, although the developer has typed:.

This stream is open and ready to accept output data. Typically, this stream corresponds to the display output or another output target specified by the host environment or user. This article is an English version of an article which is originally in the Chinese language on aliyun. May 15, Skip to content Java. What is the difference between System. Both statements use different output streams.

In the code snippet System.