Java String replaceFirst() method

This method replace the first substring with user specified String.

Syntax:

public String replaceFirst(String Regexp, String Replacement)

Parameter:

Regexp : Regular Expression

Replacement : the String which would replace found expression

Return: a string

Java String replaceFirst() Example 1

public class JavaStringReplaceFirstEx1
{
   public static void main(String args[])
   {
      String s1 = new String("example.com");
      String s2 = s1.replaceFirst("(.*)example(.*)", "tutorialandexample.com");
      System.out.println(s2);     
   }
}

Output:

tutorialandexample.com

Java String replaceFirst() Example 2

public class JavaStringReplaceFirstEx2{
   public static void main(String args[]){
       String str = new String("The replaceFirst method Tutorial");
      System.out.println(str.replaceFirst("The", "Java String"));//replacing The with Java String
   }
}

Output:

Java String replaceFirst method Tutorial

Java String replaceFirst() Example 3

import java.io.*;
public class JavaStringReplaceFirstEx3
{
   public static void main(String args[])
   {
      String Str = new String("Welcome to tutorial.com");
      System.out.println();
      System.out.print("Return Value :" );
      System.out.println(Str.replaceFirst("(.*)tutorial(.*)", "java Programming"));
      System.out.print("Return Value :" );
      System.out.println(Str.replaceFirst("tutorial", " tutorialandexample"));
      System.out.println();
   }
}

Output:

Return Value :java Programming

Return Value :

Welcome to tutorialandexample.com

Java String replaceFirst() Example 4

public class JavaStringReplaceFirstEx4
{
   public static void main(String args[])
   {
       String str = new String("tutorialandexample.com");
       System.out.println("Site name:" +str);
       System.out.println();
       System.out.print("String after replacing Site name:" );
       System.out.println(str.replaceFirst("com", "net"));    
   }


}

Output:

Site name:tutorialandexample.com
String after replacing Site name:tutorialandexample.net