public String replaceFirst(String regex, String replacement)

import java.io.*;
public class Test {

   public static void main(String args[]) {
      String Str = new String("Welcome to Tutorialspoint.com");

      System.out.print("Return Value :" );
      System.out.println(Str.replaceFirst("(.*)Tutorials(.*)", "AMROOD"));

      System.out.print("Return Value :" );
      System.out.println(Str.replaceFirst("Tutorials", "AMROOD"));
   }
}

Return Value :AMROOD
Return Value :Welcome to AMROODpoint.com