Reverse a string array !!

Problem statement: Reverse a string array in java !
Using for Loop:

1. public class ReverseStringArrayExe1 {
2. public static void main(String[] args) {
3. 
   
4. String a[] = { "apples", "tomatoes", "bananas", "guavas", "pineapples" };
5. for (int i = 0; i < a.length / 2; i++) {
6. Object temp = a[i];
7. a[i] = a[a.length - 1 - i];
8. a[a.length - 1 - i] = (String) temp;
9. 
   
10. }
11. for (String s : a) {
12. System.out.print(s + " ");
13. 
    
14. }
15. }
16. }

Output: 
pineapples guavas bananas tomatoes apples
Time complexity: O(n/2)

Using while Loop:

1. public class ReverseStringArray {
2. public static void main(String[] args) {
3. String a[] = { "apples", "tomatoes", "bananas", "guavas", "pineapples" };
4. int end = a.length - 1;
5. int start = 0;
6. String temp;
7. while (start < end) {
8. temp = a[start];
9. a[start] = a[end];
10. a[end] = temp;
11. start++;
12. end--;
13. }
14. for (String i : a) {
15. System.out.print(i + " ");
16. }
17. }
18. }

Output:

pineapples guavas bananas tomatoes apples

Time complexity: O(n/2)

Using Java 8 Stream API:

1. import java.util.stream.IntStream;
2. 
   
3. public class ReverseArrayUsingStream {
4. public static void main(String[] args) {
5. String a[] = { "apples", "tomatoes", "bananas", "guavas", "pineapples" };
6. reverseUsingStream(a);
7. }
8. 
   
9. static void reverseUsingStream(Object a[]) {
10. 
    
11. Object rev[] =IntStream.rangeClosed(1, a.length).mapToObj(i -> a[a.length - i]).toArray();
12. for (Object s : rev) {
13. System.out.print(s + " ");
14. }
15. }
16. }

Output:

pineapples guavas bananas tomatoes apples 

Using Collections.reverse() :

1. import java.util.List;
2. import java.util.Arrays;
3. import java.util.Collections;
4. 
   
5. public class ReverseArrayCollections {
6. public static void main(String[] args) {
7. String a[] = { "apples", "tomatoes", "bananas", "guavas", "pineapples" };
8. reverseUsingCollectionsUtils(a);
9. }
10. static void reverseUsingCollectionsUtils(Object[] array) {
11. List<Object> list = Arrays.asList(array);
12. Collections.reverse(list);
13. for (Object i : list) {
14. System.out.print(i + " ");
15. }
16. }
17. }

Output:

pineapples guavas bananas tomatoes apples