Java Program to Replace Multiple Characters in a String️‍🔥

Q: What is Java Program to Replace Multiple Characters in a String?

In this article, we will learn Java Program to Replace Multiple Characters in a String,This free JAVA tutorial for complete beginners will help you learn JAVA from scratch.

In this program, we will be discussing various methods for replacing multiple characters in String. This can be done using the methods listed below:

Using String.replace() method
Using replaceAll() method
Using replaceFirst() method

Method 1: Using String.replace() method

This method returns a new string resulting from replacing all occurrences of old characters in the string with new characters.

Syntax:

public String replace(char oldch, char newch)

Parameters:

The old character.
The new character.

Return Value: It returns a string derived from this string by replacing every occurrence of old character with a new character.

Example

Java

// Java code to demonstrate the 
// working of replace() 
public class rep1 { 
public static void main(String args[]) { 
          
    // Initialising String 
    String Str = new String("Welcome to w3wiki"); 
          
    // Using replace to replace characters 
    System.out.print("After replacing all o with T : " ); 
    System.out.println(Str.replace('o', 'T')); 
          
    // Using replace to replace characters 
    System.out.print("After replacing all e with D : " ); 
    System.out.println(Str.replace('e', 'D')); 
          
} 
} 

Output

After replacing all o with T : WelcTme tT BeginnerfTrBeginner
After replacing all e with D : WDlcomD to gDDksforgDDks

Method 2: Using replaceAll() method

This method replaces each substring of the string that matches the given regular expression with the given replace_str.

Syntax:

public String replaceAll(String regex, String replace_str)

Parameters:

regex: the regular expression to which this string is to be matched.
replace_str: the string which would replace found expression.

Return Value: This method returns the resulting String.

Example

Java

// Java code to demonstrate the 
// working of replaceAll() 
public class rep2 { 
public static void main(String args[]) { 
          
    // Initialising String 
    String Str = new String("Welcome to w3wiki"); 
          
    // original string 
    System.out.print("Original String : " ); 
    System.out.println(Str); 
          
    // Using replaceAll to replace regex with replace_str 
    System.out.print("After replacing regex with replace_str : " ); 
    System.out.println(Str.replaceAll("(.*)Beginner(.*)", "AKSHIT SAXENA")); 
          
} 
} 

Output

Original String : Welcome to w3wiki
After replacing regex with replace_str : AKSHIT SAXENA

Method 3: Using replaceFirst() method

This method replaces the first substring of this string that matches the given regular expression with the given replace_str.

Syntax:

public String replaceFirst(String regex, String replace_str)

Parameters

regex: The regular expression to which this string is to be matched.
replace_str: The string which would replace found expression.

Return value: This method returns a resulting string.

Example

Java

// Java code to demonstrate the 
// working of replaceFirst() 
public class rep3 { 
public static void main(String args[]) { 
          
    // Initialising String 
    String Str = new String("Welcome to w3wiki"); 
          
    // original string 
    System.out.print("Original String : " ); 
    System.out.println(Str); 
          
    // Using replaceFirst to replace regex with replace_str 
    // Replaces 1st occurrence of Beginner with ASTHA 
    System.out.print("After replacing 1st occurrence of regex with replace_str : " ); 
    System.out.println(Str.replaceFirst("Beginner", "Akshit")); 
          
} 
} 

Output

Original String : Welcome to w3wiki
After replacing 1st occurrence of regex with replace_str : Welcome to AkshitforBeginner