Class IO
java.lang.Object
java.io.IO
IO is a preview API of the Java platform.
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 SummaryModifier and TypeMethodDescriptionstatic voidWrites a string representation of the specified object to the system console and then flushes that console.static voidprintln()Terminates the current line on the system console and then flushes that console.static voidWrites a string representation of the specified object to the system console, terminates the line and then flushes that console.static Stringreadln()Reads a single line of text from the system console.static StringWrites a prompt as if by callingprint, then reads a single line of text from the system console.
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Method Details- 
printlnWrites 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 onSystem.console().- Parameters:
- obj- the object to print, may be- null
- Throws:
- IOError- if- System.console()returns- null, or if an I/O error occurs
 
- 
println
- 
printWrites 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 onSystem.console().- Parameters:
- obj- the object to print, may be- null
- Throws:
- IOError- if- System.console()returns- null, or if an I/O error occurs
 
- 
readlnWrites a prompt as if by callingprint, then reads a single line of text from the system console.The effect is as if readln(prompt)PREVIEW had been called onSystem.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 nullif 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
 
- 
readlnReads a single line of text from the system console.The effect is as if readln()PREVIEW had been called onSystem.console().- Returns:
- a string containing the line read from the system console, not
 including any line-termination characters. Returns nullif 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
- Since:
- 24
 
 
- 
IOwhen preview features are enabled.