Java I/O Streams

In Java, streams are the sequence of data that are read from the source and written to the destination.

An input stream is used to read data from the source. And, an output stream is used to write data to the destination.

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!"); 
    }
}

For example, in our first Hello World example, we have used System.out to print a string. Here, the System.out is a type of output stream.

Similarly, there are input streams to take input.

We will learn about input streams and output streams in detail in the later tutorials.

Types of Streams

Depending upon the data a stream holds, it can be classified into:

• Byte Stream
• Character Stream

Byte Stream

Byte stream is used to read and write a single byte (8 bits) of data.

All byte stream classes are derived from base abstract classes called InputStream and OutputStream.

To learn more, visit

• Java InputStream Class
• Java OutputStream Class

Character Stream

Character stream is used to read and write a single character of data.

All the character stream classes are derived from base abstract classes Reader and Writer.

To learn more, visit

• Java Reader Class
• Java Writer Class