Core Java. Swaping first and last words in sentence. Bug

I would like to make a piece of code that swap first and last words in sentence. I come up with some solution as you can see below. However, the program doesn't work well. Please help me to find mistake. You code will be much appreciated !
NOW:
input : "London is the capital of UK"
Output : "UK is the capital of UK London "

Should be :
input : "London is the capital of UK"
Output : "UK is the capital of London "

Looking forwards for help from you dear Experts !

package TaskCh;
//import java.util.Scanner;

public class TaskCh {


	public static void main(String[] args) {
	   //  System.out.println("Enter line of text.");
	   // Scanner kb = new Scanner(System.in);
	    String s = "London is the capital of UK" ;  // kb.nextLine(); // Read the whole line instead of word by word
	    System.out.println("Original line is  : ");
	    System.out.println(s);
	    String[] words = s.split("\\s+"); // Split on any whitespace

	    if (words.length > 1) { 
	                     
	    	// Swap first and last words  	
	        s = words[words.length-1] + " " +  s.substring(s.indexOf(words[1], words[0].length() -2 )) + " " + words[0].toLowerCase();

	        s = s.substring(0, 1).toUpperCase() + s.substring(1); // 

	    }

	    System.out.println("\n\n\nModified line is :");
	    System.out.println(s);
	}

}

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SunnyXAsked:
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awking00Information Technology SpecialistCommented:
Because I got my hands slapped for providing full code to your previous question, I'm taking a little different approach to this one.
Define a new string as the first word as the substring of the string up to the space. Define a new string as the last word as the substring starting with the last space (plus one more character). Define a new string as the middle replacing the first word and the last word. The output string should then simply be last word + middle + first word. Take a try at doing that.
Moussa MokhtariEnterpreneurCommented:
@Sunny
here you go
package TaskCh;
//import java.util.Scanner;
import java.util.Arrays;
public class TaskCh {


	public static void main(String[] args) {
	   //  System.out.println("Enter line of text.");
	   // Scanner kb = new Scanner(System.in);
	      String s = "London is the capital of UK" ;  // kb.nextLine(); // Read the whole line instead of word by word
	    System.out.println("Original line is  : ");
	    System.out.println(s);
	    String[] words = s.split("\\s+"); // Split on any whitespace

	    if (words.length > 1) { 
	        String lastword = words[words.length-1];
	        String firstword = words[0];
	        words[0] = lastword;
	        words[words.length-1] = firstword;

	        s = Arrays.toString(words).replaceAll("[\\[\\]\\,]", "");
	    }

	    System.out.println("\n\n\nModified line is :");
	    System.out.println(s);
	    }

}

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CEHJCommented:
Homework done?
HTML5 and CSS3 Fundamentals

Build a website from the ground up by first learning the fundamentals of HTML5 and CSS3, the two popular programming languages used to present content online. HTML deals with fonts, colors, graphics, and hyperlinks, while CSS describes how HTML elements are to be displayed.

awking00Information Technology SpecialistCommented:
While I would have preferred you attempted to write the code using my directions, since full code is being supplied, this is how I would have gone about it (very simple) -
String str = "London is the capital of UK";
String first = str.substring(0,indexOf(" "));
String last = str.substring(lastIndexOf(" ") + 1);
String middle = str.replace(first,"").replace(last,"");
String output =  last + middle + first;
SunnyXAuthor Commented:
Everybody thx for your help ! :)
SunnyXAuthor Commented:
awking00, I'm sorry. I just saw your last post :( I'm actually submitting the close of question, webpage updated that your valuable comment come up :( once again sorry
CEHJCommented:
s = s.replaceAll("^(\\w*)(.*?)(\\w*)$", "$3$2$1");

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