ByteArrayInputStream markSupported() method in Java with Examples

The markSupported() method is a built-in method of the Java.io.ByteArrayInputStream method tests if this input stream supports the mark and reset methods. The markSupported method of ByteArrayInputStreamInputStream returns true always

Syntax: 

public boolean markSupported()

Parameters: The function does not accepts any parameter. 
Return Value: The function returns a boolean value. It returns true if this stream instance supports the mark and reset methods, else false.

Below is the implementation of the above function:

Program 1: 

Java

// Java program to implement
// the above function
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception
    {

        byte[] buf = { 5, 6, 7, 8, 9 };

        // Create new byte array input stream
        ByteArrayInputStream exam
            = new ByteArrayInputStream(buf);

        // print bytes
        System.out.println(exam.read());
        System.out.println(exam.read());
        System.out.println(exam.read());

        System.out.println("Mark() invocation");

        // Use of markSupported
        boolean check = exam.markSupported();
        System.out.println("markSupported() : "
                           + check);

        if (exam.markSupported()) {

            // Use of reset() method :
            // repositioning the stream to marked positions.
            exam.reset();

            System.out.println("\nreset() invoked");
            System.out.println(exam.read());
            System.out.println(exam.read());
        }
        else {
            System.out.println("reset() method not supported.");
        }
    }
}

Output:

5
6
7
Mark() invocation
markSupported() : true

reset() invoked
5
6

Program 2: 

Java

// Java program to implement
// the above function
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception
    {

        byte[] buf = { 1, 2, 3 };

        // Create new byte array input stream
        ByteArrayInputStream exam
            = new ByteArrayInputStream(buf);

        // print bytes
        System.out.println(exam.read());
        System.out.println(exam.read());
        System.out.println(exam.read());

        // Use of markSupported
        boolean check = exam.markSupported();

        System.out.println("markSupported() : "
                           + check);

        if (exam.markSupported()) {

            // Use of reset() method :
            // repositioning the stream to marked positions
            exam.reset();

            System.out.println("\nreset() invoked");
            System.out.println(exam.read());
            System.out.println(exam.read());
        }
        else {
            System.out.println("reset() method not supported.");
        }
    }
}

Output:

1
2
3
markSupported() : true

reset() invoked
1
2

Reference: https://docs.oracle.com/javase/10/docs/api/java/io/ByteArrayInputStream.html#markSupported()