How to count replace first occurrence of a string in Java

Problem Description

How to count replace first occurrence of a String?

Solution

Following example demonstrates how to replace first occurrence of a String in a String using replaceFirst() method of a Matcher class.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
   public static void main(String args[]) {
      Pattern p = Pattern.compile("hello");
      String instring = "hello hello hello.";
      System.out.println("initial String: "+ instring);
      Matcher m = p.matcher(instring);
      String tmp = m.replaceFirst("Java");
      System.out.println("String after replacing 1st Match: " +tmp);
   }
}

Result

The above code sample will produce the following result.

initial String: hello hello hello.
String after replacing 1st Match: Java hello hello.