Java I/O (Input and Output) is used to process the input and produce the output based on the input.
Java uses the concept of stream to make I/O operation fast. The java.io package contains all the classes required for input and output operations.
We can perform file handling in java by java IO API.
Stream
A stream is a sequence of data.In Java a stream is composed of bytes. It’s called a stream because it’s like a stream of water that continues to flow.
In java, 3 streams are created for us automatically. All these streams are attached with console.
1) System.out: standard output stream
2) System.in: standard input stream
3) System.err: standard error stream
Let’s see the code to print output and error message to the console.
- System.out.println(“simple message”);
- System.err.println(“error message”);
Let’s see the code to get input from console.
- int i=System.in.read();//returns ASCII code of 1st character
- System.out.println((char)i);//will print the character
QCOM 