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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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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LVL 33

awking00Information Technology SpecialistCommented: 2016-07-27

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.

LVL 9

Moussa MokhtariEnterpreneurCommented: 2016-07-27

@Sunny
here you go

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LVL 87

CEHJCommented: 2016-07-27

Homework done?

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: 2016-07-27

Everybody thx for your help ! :)

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

s = s.replaceAll("^(\\w*)(.*?)(\\w*)$", "$3$2$1");

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

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