How to replace a substring inside a string by another one ?

This example describes how replace method of java String class can be used to replace character or substring by new one.

public class StringReplaceEmp{
   public static void main(String args[]){
      String str = "Hello World";
      System.out.println( str.replace( 'H','W' ) );
      System.out.println( str.replaceFirst("He", "Wa") );
      System.out.println( str.replaceAll("He", "Ha") );
   }
}


Result
The above code sample will produce the following result.

Wello World
Wallo World
Hallo World

How to search the last position of a substring ?

This example shows how to determine the last position of a substring inside a string with the help of strOrig.lastIndexOf(Stringname) method.

public class SearchlastString {
   public static void main(String[] args) {
      String strOrig = "Hello world ,Hello Reader";
      int lastIndex = strOrig.lastIndexOf("Hello");
     
      if(lastIndex == - 1){
         System.out.println("Hello not found");
      } else {
         System.out.println("Last occurrence of Hello is at index "+ lastIndex);
      }
   }
}

Result

The above code sample will produce the following result.

Last occurrence of Hello is at index 13

Example

This another example shows how to determine the last position of a substring inside a string with the help of strOrig.lastIndexOf(Stringname) method.

public class HelloWorld{
   public static void main(String []args) {
      String t1 = "Tutorialspoint";
      int index = t1.lastIndexOf("p");
      System.out.println(index);
   }
}

The above code sample will produce the following result.

9