String Replace - using replace function in Java

 
public class StringReplace{
 
  public static void main(String args[]){
    String str="Replace Region";
    System.out.println( str.replace( 'R','A' ) );
    System.out.println( str.replaceFirst("Re", "Ra") );
    System.out.println( str.replaceAll("Re", "Ra") );
 
  }
 
}