Writer append(CharSequence, int, int) in Java

append(CharSequence, int, int): This method is available in the java.io.Writer class of Java.

Syntax:

Writer java.io.Writer.append(CharSequence csq, int start, int end) throws IOException

This method takes three arguments. This method appends a subsequence of the specified character sequence to this writer.Appendable.

Parameters: Three parameters are required for this method.

csq: The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".

start: The index of the first character in the subsequence.

end: The index of the character following the last character in the subsequence.

Returns: This writer.

Throws:

1. IndexOutOfBoundsException - If start or end are negative, start is greater than end, or end is greater than csq.length().

2. IOException - If an I/O error occurs.

Approach 1: When no exception

Java

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

public class Writerappend3 {
    public static void main(String[] args) throws IOException {

        Writer writer = new StringWriter();

        CharSequence csq = new String("HELLO JAVA");
        int start = 0, end = 5;
        writer.append(csq, start, end);

        System.out.println("Successfully append");

        writer.close();
    }
}

Output:

Successfully append

Approach 2: IndexOutOfBoundsException 

Java

package com.Writer;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

public class Writerappend3 {
    public static void main(String[] args) throws IOException {

        Writer writer = new StringWriter();

        CharSequence csq = new String("HELLO JAVA");
        int start = 0, end = 15;
        writer.append(csq, start, end);

        System.out.println("Successfully append");

        writer.close();
    }
}

Output:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: begin 0, end 15, length 10
	at java.base/java.lang.String.checkBoundsBeginEnd(String.java:3734)
	at java.base/java.lang.String.substring(String.java:1903)
	at java.base/java.lang.String.subSequence(String.java:1942)
	at java.base/java.io.StringWriter.append(StringWriter.java:190)
	at java.base/java.io.StringWriter.append(StringWriter.java:41)
	at com.Writer.Writerappend3.main(Writerappend3.java:14)

Some other methods of Writer

append(char): This method appends the specified character to this writer.

append(CharSequence): This method appends the specified character sequence to this writer.

append(CharSequence, int, int): This method appends a subsequence of the specified character sequence to this writer.Appendable.

close(): This method closes the stream, flushing it first.

flush(): This method flushes the stream.

Writer.nullWriter(): This method returns a new Writer who discards all characters

write(char[]): This method writes an array of characters.

write(int): This method writes a single character.

write(String): This method writes a string.

write(char[], int, int): This method writes a portion of an array of characters.

write(String, int, int): This method writes a portion of a string.