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

Question:

How to replace a word inside a string by a different word ?

Answer:

Using the String replace() method.

Code:

public class ReplaceSubString {
 
   public static void main(String[] args) {
 
      String str1= "The cat in the hat.";
      String str2 = str1.replace( "cat","dog" );
 
      System.out.println("Original string: " + str1);
      System.out.println("New string:      " + str2);
 
   }
}

Output:

$ java ReplaceSubString 
Original string: The cat in the hat.
New string:      The dog in the hat.