recursive reverse string java code example

Example 1: reverse array in java

int length = array.length;
		for(int i=0;i<length/2;i++) {
			int swap = array[i];
			array[i] = array[length-i-1];
			array[length-i-1] = swap;
		}
or
Collections.reverse(Arrays.asList(array));

Example 2: reverse string using recursion java with explanation

public static String reverse(String str) {
    if ((null == str) || (str.length() <= 1)) {
        return str;
    }
    return reverse(str.substring(1)) + str.charAt(0);
}

Example 3: reverse string using recursion java with explanation

public class Test {

    private static int i = 0;

    public static void main(String args[]) {
        reverse("Hello");
    }

    public static String reverse(String str) {
        int localI = i++;
        if ((null == str) || (str.length()  <= 1)) {
            return str;
        }
        System.out.println("Step " + localI + ": " + str.substring(1) + " / " + str.charAt(0));
        String reversed = reverse(str.substring(1)) + str.charAt(0);

        System.out.println("Step " + localI + " returns: " + reversed);
        return reversed;
    }
}