/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
class Ideone {
	public static void main (String[] args) throws java.lang.Exception {
		final int[] arrayOdd = {1, 2, 3, 4, 5};
		final int[] arrayEven = {1, 2, 3, 4, 5, 6};
 
		System.out.println(String.format("Even: %s \nOdd:%s",
				Arrays.toString(swap(arrayEven)),
				Arrays.toString(swap(arrayOdd))));
	}
 
	private static int[] swap(final int[] input) {
		final int length = input.length;
 
		if (length < 2) {
			return input;
		}
 
    	int i = 1;
    	while (i < length) {
    		input[i] = input[i] ^ input[i-1] ^ (input[i-1] = input[i]);
    		i+=2;
    	}
 
    	return input;
	}
}

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