StringReader reset() method in Java with Examples

The reset() method of StringReader Class in Java is used to reset the stream. After reset, if the stream has been marked, then this method attempts to reposition it at the mark, else it will try to position it to the starting.

Syntax:

public void reset()

Parameters: This method do not accepts any parameter.

Return Value: This method do not returns any value.

Exception: This method throws IOException:

• if some error occurs while input output
• if the stream has not been marked
• if the mark has been invalidated
• if the reset() method is not supported.

Below methods illustrates the working of reset() method:

Program 1:

// Java program to demonstrate
// StringReader reset() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {
            String str = "GeeksForGeeks";

            // Create a StringReader instance
            StringReader reader
                = new StringReader(str);

            // Get the character
            // to be read from the stream
            int ch;

            // Read the first 10 characters
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            for (int i = 0; i < 10; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }

            System.out.println();

            // mark the stream for
            // 5 characters using reset()
            reader.mark(5);

            // reset the stream position
            reader.reset();

            // Read the 5 characters from marked position
            // to this reader using read() method
            for (int i = 0; i < 5; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

GeeksForGe
eks??

Program 2:

// Java program to demonstrate
// StringReader reset() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {
            String str = "GeeksForGeeks";

            // Create a StringReader instance
            StringReader reader
                = new StringReader(str);

            // Get the character
            // to be read from the stream
            int ch;

            // Read the first 10 characters
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            for (int i = 0; i < 10; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }

            System.out.println();

            // reset the stream position
            reader.reset();

            // Read the 5 characters from marked position
            // to this reader using read() method
            for (int i = 0; i < 5; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

GeeksForGe
Geeks

Reference: https://docs.oracle.com/javase/9/docs/api/java/io/StringReader.html#reset–