Reader markSupported() in Java

markSupported(): This method is available in the java.io.Reader class of Java.

Syntax:

boolean java.io.Reader.markSupported()

This method tells whether this stream supports the mark() operation. The default implementation always returns false.

Note: Subclasses should override this method.

Parameters: NA

Returns: true if and only if this stream supports the mark operation.

Exceptions: NA

Approach 1: When the stream supports the mark operation.

Java

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class ReadermarkSupported {
    public static void main(String[] args) throws IOException {

        Reader reader = new StringReader("HELLO");

        System.out.println(reader.markSupported());
        reader.close();

    }
}

Output:

true

Approach 2: When the stream does not support the mark operation.

Java

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

public class ReadermarkSupported {
    public static void main(String[] args) throws IOException {

        Reader reader = new FileReader("D:\\hello.txt");

        System.out.println(reader.markSupported());
        reader.close();

    }
}

Output:

false

Some other methods of Reader

close(): This method closes the stream and releases any system resources associated with it.

mark(int): This method marks the present position in the stream.

markSupported(): This method tells whether this stream supports the mark() operation. 

Reader.nullReader(): This method returns a new Reader that reads no characters.

read(): This method reads a single character.

read(char[]): This method reads characters into an array.

read(CharBuffer): This method attempts to read characters into the specified character buffer.

read(char[], int, int): This method reads characters into a portion of an array.

ready(): This method tells whether this stream is ready to be read.

reset(): This method resets the stream.

skip(long): This method skips characters.

transferTo(Writer): This method reads all characters from this reader and writes the characters to the given writer in the order that they are read.