Class IO

java.lang.Object
java.io.IO
public final class IO extends Object
IO is a preview API of the Java platform.
Programs can only use IO when preview features are enabled.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A collection of static convenience methods that provide access to system console for implicitly declared classes.

Each of this class' methods throws IOError if the system console is null; otherwise, the effect is as if a similarly-named method had been called on that console.

Input and output from methods in this class use the character set of the system console as specified by Console.charset().

Since:
23

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    print(Object obj)
    Writes a string representation of the specified object to the system console and then flushes that console.
    static void
    println(Object obj)
    Writes a string representation of the specified object to the system console, terminates the line and then flushes that console.
    static String
    readln(String prompt)
    Writes a prompt as if by calling print, then reads a single line of text from the system console.

    Methods declared in class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • println

      public static void println(Object obj)
      Writes a string representation of the specified object to the system console, terminates the line and then flushes that console.

      The effect is as if println(obj)PREVIEW had been called on System.console().

      Parameters:
      obj - the object to print, may be null
      Throws:
      IOError - if System.console() returns null, or if an I/O error occurs

    • print

      public static void print(Object obj)
      Writes a string representation of the specified object to the system console and then flushes that console.

      The effect is as if print(obj)PREVIEW had been called on System.console().

      Parameters:
      obj - the object to print, may be null
      Throws:
      IOError - if System.console() returns null, or if an I/O error occurs

    • readln

      public static String readln(String prompt)
      Writes a prompt as if by calling print, then reads a single line of text from the system console.

      The effect is as if readln(prompt)PREVIEW had been called on System.console().

      Parameters:
      prompt - the prompt string, may be null
      Returns:
      a string containing the line read from the system console, not including any line-termination characters. Returns null if an end of stream has been reached without having read any characters.
      Throws:
      IOError - if System.console() returns null, or if an I/O error occurs