StringBuilder append() Method in Java With Examples

20 June 2025

0

The java.lang.StringBuilder.append() method is used to append the string representation of some argument to the sequence. There are 13 ways/forms in which the append() method can be used by the passing of various types of arguments:

StringBuilder append(boolean a) :The java.lang.StringBuilder.append(boolean a) is an inbuilt method in Java which is used to append the string representation of the boolean argument to a given sequence.

Syntax :

public StringBuilder append(boolean a)

Parameter: This method accepts a single parameter a of boolean type and refers to the Boolean value to be appended.

Return Value: The method returns a reference to this object.

Examples:

Input: 
string_buffer = "We are Indians" 
boolean a = true

Output: We are Indians true

Below program illustrates the java.lang.StringBuilder.append() method:

// Java program to illustrate the
// StringBuilder append(boolean a)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sb1 = new 
                      StringBuilder("Welcome to Geeksforgeeks ");
        System.out.println("Input: " + sb1);
  
        // Appending the boolean value
        sb1.append(true);
        System.out.println("Output: " + sb1);
  
        System.out.println();
  
        StringBuilder sb2 = new StringBuilder("We fail- ");
        System.out.println("Input: " + sb2);
  
        // Appending the boolean value
        sb2.append(false);
        System.out.println("Output: " + sb2);
    }
}

Output:

Input: Welcome to Geeksforgeeks 
Output: Welcome to Geeksforgeeks true

Input: We fail- 
Output: We fail- false

java.lang.StringBuilder.append(char a): This is an inbuilt method in Java which is used to append the string representation of the char argument to the given sequence. The char argument is appended to the contents of this StringBuilder sequence.

Syntax :

public StringBuilder append(char a)

Parameter: The method accepts a single parameter a which is the Char value whose string representation is to be appended.

Return Value: The method returns a string object after the append operation is performed.
Examples :

Input :
StringBuilder = I love my Country 
char a = A

Output: I love my Country A

Below programs illustrate the java.lang.StringBuilder.append(char a) method.

// Java program to illustrate the
// java.lang.StringBuilder.append(char a)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
          
        StringBuilder sbf = new 
                       StringBuilder("Welcome geeks!");
                System.out.println( sbf);
  
        /* Here it appends the char argument as
        string to the StringBuilder */
        sbf.append('T');
        System.out.println("Result after"+
                                 " appending = " + sbf);
  
      
        sbf = new StringBuilder("hello world-");
                System.out.println(sbf);
        /* Here it appends the char argument as
        string to the String Builder */
        sbf.append('#');
        System.out.println("Result after appending = " 
                                                         + sbf);
    }
}

Output:

Welcome geeks!
Result after appending = Welcome geeks!T
hello world-
Result after appending = hello world-#

StringBuilder append(char[] astr): The java.lang.StringBuilder.append(char[] astr) is the inbuilt method which appends the string representation of the char array argument to this StringBuilder sequence.

Syntax :

public StringBuilder append(char[] astr)

Parameter: The method accepts a single parameter astr which are the Char sequence whose string representation is to be appended.

Return Value: The method returns a string object after the append operation is performed.
Examples:

Input :
StringBuffer  = I love my Country   
char[] astr = 'I', 'N', 'D', 'I', 'A'

Output: I love my Country INDIA

Below program illustrates the java.lang.StringBuilder.append(char[] astr) method:

// Java program to illustrate the
// java.lang.StringBuilder.append(<em>char[] astr</em>)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
          
        StringBuilder sbf = new 
                      StringBuilder("We are geeks  ");
        System.out.println(sbf);
  
        // Char array
        char[] astr = new char[] 
                          { 'G', 'E', 'E', 'k', 'S' };
  
        /* Appends string representation of char
                   array to this String Builder */
        sbf.append(astr);
    System.out.println("Result after"+
                            " appending = " + sbf);
          
        sbf = new StringBuilder("We are  -");
                System.out.println(sbf);
  
        // Char array
        astr = new char[] { 'a', 'b', 'c', 'd' };
  
        /* Appends string representation of char 
                   array to this StringBuilder */
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
    }
}

Output:

We are geeks  
Result after appending = We are geeks  GEEkS
We are  -
Result after appending = We are  -abcd

StringBuilder append(char[] cstr, int iset, int ilength) : This method appends the string representation of a subarray of the char array argument to this sequence. The Characters of the char array cstr, starting at index iset, are appended, in order, to the contents of this sequence. The length of this sequence increases by the value of ilength.

Syntax :

public StringBuilder append(char[] cstr, int iset, int ilength)

Parameter : This method accepts three parameters:

cstr – This refers to the Char sequence.
iset – This refers to the index of the first char to append.
ilength – This refers to the number of chars to append.

Return Value: The method returns a string object after the append operation is performed.
Below program illustrates the java.lang.StringBuilder.append(char[] cstr, int iset, int ilength) method.

// Java program to illustrate the
// append(char[] cstr, int iset, int ilength)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sb = new 
                              StringBuilder("Geeks");
        System.out.println("String Builder "+
                                   "before = " + sb);
  
        char[] cstr = new char[] 
          { 'f', 'o', 'r', 'G', 'e', 'e', 'k', 's','q','q' };
  
        /* appends the string representation of char array 
           argument to this String Builder with offset initially 
           at index 0 and length as 8 */
        sb.append(cstr, 0, 8);
  
        // Print the String Builder after appending
        System.out.println("After appending String Builder = " + sb);
    }
}

Output:

String Builder before = Geeks
After appending String Builder = Lazyroar

StringBuilder append(double a): This method simply appends the string representation of the double argument to this StringBuilder sequence.

Syntax :

public StringBuilder append(double val)

Parameter: The method accepts a single parameter val which refers to the decimal value whose string representation is to be appended.

Return Value: The method returns a string object after the append operation is performed.
Examples :

Input :
StringBuffer = my Country
Double a = 54.82

Output: my Country 54.82

Below program illustrates the java.lang.StringBuilder.append(double val) method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
              StringBuilder("We are geeks and its ");
  
        // Char array
        Double astr = new Double(36.47);
  
        /* Here it appends string representation of Double 
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Double(27.38);
  
        /* Here it appends string representation of Double  
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
    }
}

Output:

We are geeks and its really 
Result after appending = We are geeks and its 36.47
We are lost -
Result after appending = We are lost -27.38

StringBuilder append(float val): This method appends the string representation of the float argument to this sequence.

Syntax :

public StringBuilder append(float val)

Parameter: The method accepts a single parameter val which is the float value whose string representation is to be appended.

Return Value: StringBuilder.append(float val) method returns a reference the string object after the operation is performed.

Examples :

Input : 
StringBuilder  = I love my Country 
float a = 5.2
 
Output: I love my Country 5.2

Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Float astr = new Float(6.47);
  
        /* Here it appends string representation of 
           Float argument to this StringBuilder */
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Float(27.38);
  
        // Here it appends string representation of Float
        // argument to this String Builder
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}

Output:

We are geeks and its really 
Result after appending = We are geeks and its 6.47
We are lost -
Result after appending = We are lost -27.38

StringBuilder append(int val) This method simply appends the string representation of the int argument to this StringBuilder sequence.
Syntax :

public StringBuilder append(int val)

Parameter: The method accepts a single parameter val which is an integer value on which the operation is supposed to be performed.

Return Value: The method returns a reference to this object.

Examples :

Input :
StringBuilder = I love my Country  
int a = 55

Output: I love my Country 55

Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Integer astr = new Integer(827);
  
        /* Here it appends string representation of 
           Integer argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Integer(515);
  
        // Here it appends string representation of Integer
        // argument to this StringBuilder
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}

Output:

We are geeks and its really 
Result after appending = We are geeks and its 827
We are lost -
Result after appending = We are lost -515

StringBuilder append(Long val) : This method simply appends the string representation of the long argument to this StringBuilder sequence.

Syntax :

public StringBuilder append(Long val)

Parameter: The method accepts a single parameter val which is the long value.

Return Value: The method returns a string object after the append operation is performed.
Examples :

Input :
StringBuilder  = I love my Country
Long a = 591995

Output: I love my Country 591995

Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Long astr = new Long(827);
  
        /* Here it appends string representation of 
           Long argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Long(515);
  
        /* Here it appends string representation of Long 
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}

Output:

We are geeks and its really 
Result after appending = We are geeks and its 827
We are lost -
Result after appending = We are lost -515

StringBuilder append(CharSequence a): This method is used to append the specified CharSequence to this sequence.

Syntax :

public StringBuilder append(CharSequence a)

Parameter: The method accepts a single parameter a which is the CharSequence value.

Return Value: The method returns a string object after the append operation is performed.

Examples :

Input :
StringBuilder  = "I love my Country" 
CharSequence a = " India"

Output : I love my Country India

Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        CharSequence chSeq = "geeks";
  
        // Appends the CharSequence
        sbf.append(chSeq);
  
        // Print the String Builder after appending
        System.out.println("After append = " + sbf);
    }
}

Output:

String Builder = Geeksfor
After append = Geeksforgeeks

StringBuilder append(CharSequence chseq, int start, int end) : This method is used to append a subsequence of the specified CharSequence to this StringBuilder.

Syntax :

StringBuilder append(CharSequence chseq, int start, int end)

Parameter : The method accepts three parameters:

chseq(CharSequence): This refers to the CharSequence value.
start(Integer): This refers to the starting index of the subsequence to be appended..
end(Integer): This refers to the end index of the subsequence to be appended.

Return Value : The method returns the string after the append operation is performed.

Examples :

Input :
StringBuilder = Geeksforgeeks
CharSequence chseq = abcd1234
int start = 2
int end = 7

Output :Geeksforgeekscd123

Below program illustrates the java.lang.StringBuilder.append() method:

// Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new 
              StringBuilder("We are the ");
        System.out.println("String builder= "
                                      + sbf);
  
        CharSequence chSeq = "wegeekss";
  
        /* It appends the CharSequence with  
           start index 2 and end index 4 */
        sbf.append(chSeq, 2, 7);
  
        System.out.println("After append string"+
                             " buffer = " + sbf);
    }
}

Output:

String builder= We are the 
After append string buffer = We are the geeks

StringBuilder append(Object obj) : This method is used to append the string representation of the Object argument to the StringBuilder.

Syntax :

StringBuilder append(Object obj)

Parameter: The method accepts a single parameter obj which refers to the object needed to be appended.

Return Value: The method returns the string after performing the append operation.

Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        Object objectvalue = "geeks";
  
        // Here it appends the Object value
        sbf.append(objectvalue);
  
        System.out.println("After appending result is = "+sbf);
    }
}

Output:

String Builder = Geeksfor
After appending result is = Geeksforgeeks

StringBuilder append(String istr) : This method is used to append the specified string to this StringBuilder.
Syntax :

StringBuilder append(String istr)

Parameter: The method accepts a single parameter istr of String type which refer to the value to be appended.

Return Value : The method returns a specified string to this character sequence.
Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        String strvalue = "geeks";
  
        // Here it appends the Object value
        sbf.append(strvalue);
  
        System.out.println("After appending result is = "+sbf);
    }
}

Output:

String Builder = Geeksfor
After appending result is = Geeksforgeeks

StringBuilder append(StringBuilder sbf) : This method is used to append the specified StringBuilder to this sequence or StringBuilder.

Syntax:

public StringBuilder append(StringBuilder sbf)

Parameter: The method accepts a single parameter sbf refers to the StringBuilder to append.

Return Value : The method returns StringBuilder to this sequence.
Below program illustrates the java.lang.StringBuilder.append() method.

// Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf1 = new StringBuilder("Geeks");
        System.out.println("String Builder 1 = " + sbf1);
  
        StringBuilder sbf2 = new StringBuilder("forgeeks ");
        System.out.println("String Builder 2 = " + sbf2);
  
        // Here it appends String Builder2 to String Builder1
        sbf1.append(sbf2);
  
        System.out.println("After appending the result is = "+sbf1);
    }
}

Output:

String Builder 1 = Geeks
String Builder 2 = forgeeks 
After appending the result is = Geeksforgeeks

StringBuilder append() Method in Java With Examples

Working with Titles and Heading – Python docx Module

Creating a Receipt Calculator using Python

One Liner for Python if-elif-else Statements

LEAVE A REPLY Cancel reply

Most Popular

Android 16 QPR2 Beta 3 lands with a flurry of bug fixes

Google is working on dedicated ‘Bills’ and ‘Travel’ folders for Gmail

Mint Mobile’s big bet on 5G home internet might change everything

Interviewed With Kyle Smith – Founder and CEO of Escalated by Shauli Zacks

EDITOR PICKS

Android 16 QPR2 Beta 3 lands with a flurry of bug fixes

Google is working on dedicated ‘Bills’ and ‘Travel’ folders for Gmail

Mint Mobile’s big bet on 5G home internet might change everything

POPULAR POSTS

Android 16 QPR2 Beta 3 lands with a flurry of bug fixes

Google is working on dedicated ‘Bills’ and ‘Travel’ folders for Gmail

Mint Mobile’s big bet on 5G home internet might change everything

POPULAR CATEGORY

ABOUT US

FOLLOW US