A stream is a sequence of data. I/O streams refers to input output stream - basically reading from a source and writing to a destination.

When to use Character Stream over Byte Stream?

In Java, characters are stored using Unicode conventions. Character stream is useful when we want to process text files. These text files can be processed character by character. Character size is typically 16 bits = 2byte.

When to use Byte Stream over Character Stream?

Byte oriented reads byte by byte.  A byte stream is suitable for processing raw data like binary files.

Key points about working with streams:

1. Character stream class names end with Reader/Writer, while byte stream class names end with InputStream/OutputStream
2. Basic unbuffered streams are inefficient. For better performance, use buffered streams—BufferedReader/BufferedWriter for character streams and BufferedInputStream/BufferedOutputStream for byte streams.
3. Always close streams when you're done using them to prevent errors from corrupting the stream.

Character Stream

In Java, characters are stored using Unicode conventions. Character stream automatically allows us to read/write data character by character. For example, FileReader and FileWriter are character streams used to read from the source and write to the destination.

package com.xyz;

import java.io.FileReader;
import java.io.IOException;

//Java Program illustrate Reading
//a File in Human Readable
//Format Using FileReader Class

public class CharacterStreamDemo {
	
	// Main driver method
    public static void main(String[] args) throws IOException {

        // Initially assigning null as we have not read
        // anything
        FileReader sourceStream = null;

        // Try block to check for exceptions
        try {

            // Reading from file
            sourceStream = new FileReader(
                "C:\\\\Users\\\\Windows\\\\Documents\\\\demo.rtf");

            // Reading sourcefile and writing content to
            // target file character by character.

            int temp;

            // If there is content inside file
            // than read
            while ((temp = sourceStream.read()) != -1)
                System.out.print((char)temp);

            // Display message for successful execution of
            // program
            System.out.print(
                "Program successfully executed");
        }
        catch (Exception e) {
		        e.printStackTrace();
		    }

        // finally block that executes for sure
        // where we are closing file connections
        // to avoid memory leakage
        finally {

            // Closing stream as no longer in use
            if (sourceStream != null)
                sourceStream.close();
        }
    }

}

Byte Stream

Byte streams process data byte by byte (8 bits). For example, FileInputStream is used to read from the source and FileOutputStream to write to the destination.