The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
System provides several predefined I/O objects that are useful in a Java application that is meant to be launched from the command line. These implement the Standard I/O streams provided by most operating systems, and also a console object that is useful for entering passwords. For more information, refer to
I/O from the Command Line in the
Basic I/O lesson.