Interesting task with regular expressinos

[Bill SS]

I learn java for one year but several times ago my friend ask me a next task

There is a text consisting of words of different lengths.
Needed in a console application to add a menu with a choice of word length to be replaced by the word entered by the same panel.

Terms: code convention and two classes(OOP inheritance has to be supported)
console example:

"Please enter text"
jfkdjf klsdkdls dslklsk dkslk
"Please enter word's length to change "
6
"Please enter the words"
milk
"result is:"
milk klsdkdls dslklsk milk

import java.util.*;
public class Test {

	
	public static void main(String[] args)
	{
	
        Scanner in = new Scanner (System.in);
		
        System.out.println("Please, input text");
		String text = in.nextLine();	

		System.out.println("Please enter word's length to change");
		int length  = in.nextInt();
		Scanner in1 = new Scanner (System.in);
		
		System.out.println("Please enter the word");
		String change = in1.nextLine();
	}
	class sentence extends Test
	public class Sentence {
   private Word head;
   private Word tail;
   private int size;

   public Sentence( String sentence ) {
      String[] words =  sentence.split( "\\s+" );
      for ( String  word : words ) {
         add( word );
      }
   }

   public void add( String word ){
      //...
   }

   public Word first(){
      return head;
   }


   public Word last(){
      return tail;
   }
   
   //...

}

public class Word [I][SIZE=4]extends[/SIZE][/I] sentense {
   private Word prev;
   private Word next;
   private String item;
   
   public void setNext( Word nextOne ) {
      next = nextOne;
   }
   
   public void setPrev( Word prevOne ) {
      prev = prevOne;
   }

   public Word prev(){
      return prev;
   }
   
   public Word next(){
      return next;
   }
   
   public int length(){
      return item.length();
   }
   
   public void replace ( Sentence sentence ) {
      //...
   }
   //...

}

System.out.println ("result is"+" "+: const):
}

My question is how really abolish the code and add really useful methods in it? Can you hepl me with realization of it?
Thank you for your time guys.

[pbrockway2]

Also at javaprogrammingforums.com

@OP: If you have started a discussion in various places, please post links to let everyone know that. Everyone participating in a discussion ought, at least, to know where that discussion is taking place.

Also bear in mind that many people are a little reluctant to participate in discussion like this for fear of wasting their time answering a question that might have been answered elsewhere.

[Bill SS]

I really wonder to know how to resolve this task... I dont discussed anything in javaprogrammingforums.com
I started to resolve it only there.
Sorry for double-post task-information especiallu fpr post it in javaprogrammingforums.com

[Bill SS]

So guys give give some code-hints for my developments with friend's task/// I really have ability to resolve that task.