Lambda Expression to reverse a string - Java

Question

String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars", 
                  "Jupiter", "Saturn", "Uranus", "Neptune" };

I have a simple array of planet names and I want to reverse each name that was added to the array (not the string order).
I continue to struggle with lambda syntax:

Arrays.sort(planets, (first, second) -> new StringBuilder(first).reverse().toString());
System.out.println(Arrays.toString(planets));

Currently I get:

Multiple markers at this line

• The method reverse() in the type StringBuilder is not applicable for the arguments (String)
• Type mismatch: cannot convert from String to int

Response:

Thank you all for suggestions... asList got me close. I still didn't sort correctly.

So i need to find a way to make array.sort work because this was the assignment (to take array.sort and lambda it).

I have pinged the instructor to ask for clarification here, but i am running out of time.

Here is my work attempting to keep array.sort

            // lambda expression , long to short
        System.out.println("5) Sorted by length (descending):");
        Arrays.sort(planets, (first, second) -> second.length() - first.length());
        System.out.println(Arrays.toString(planets));   

        // lambda expression , reverse the name , then sort in ascending order
        // hint use  new StringBuilder(first).reverse().toString() to reverse the string
        System.out.println("6) Sorted in dictionary order of the reversed name (ascending)");
        Arrays.sort(planets, (first, second) -> new StringBuilder(first).reverse().toString().compareTo(second));
        System.out.println(Arrays.toString(planets));

        // lambda expression , reverse the name , then sort in descending order
        System.out.println("7) Sorted in dictionary order of the reversed name (descending)");
        Arrays.sort(planets, (first, second) -> new StringBuilder(second).reverse().toString().compareTo(first));
        System.out.println(Arrays.toString(planets));

What I cannot for the life of me figure out here is that all 3 expressions get me exactly the same result... each of those gives me the original array sorted longest to shortest.

This is my result:

5) Sorted by length (descending): [Neptune, Mercury, Jupiter, Uranus, Saturn, Venus, Earth, Mars]

6) Sorted in dictionary order of the reversed name (ascending) [Neptune, Mercury, Jupiter, Uranus, Saturn, Venus, Earth, Mars]

7) Sorted in dictionary order of the reversed name (descending) [Neptune, Mercury, Jupiter, Uranus, Saturn, Venus, Earth, Mars]

Answer 1

An alternative solution which does not use Stream API and updates the strings in-place:

Arrays.asList(planets).replaceAll(s -> new StringBuilder(s).reverse().toString());

Demo:

String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars", 
        "Jupiter", "Saturn", "Uranus", "Neptune" };
Arrays.asList(planets).replaceAll(s -> new StringBuilder(s).reverse().toString());
System.out.println(Arrays.toString(planets));
// [yrucreM, suneV, htraE, sraM, retipuJ, nrutaS, sunarU, enutpeN]